Physics Letters B

Published by Elsevier BV

Print ISSN: 0370-2693


Production of 3H at large momentum in α−12C collisions at 2A GeV
  • Article

June 1992


34 Reads



Calculations of the longitudinal and transverse momentum distributions for 3H production at large momentum in alpha-12C collisions near 2 A GeV are compared to experiment. Triton exchange and final-state interactions are shown to represent large corrections to the impulse approximation for proton knockout. A method for calculating interference effects for inelastic fragmentation is discussed. Good agreement with experiment is found using a phenomenological overlap function for 3H-p successful in describing 3H production in pion-induced reactions. Comparisons to momentum distributions obtained through (p, 2p) and (e, ep) reactions on 4He are made.

Exclusive measurements of mean pion multiplicities in 4He-nucleus reactions from 200 to 800 MeV/nucleon

December 1987


10 Reads






Mean multiplicities of pi+ and pi- in 4He collisions with C, Cu, and Pb at 200, 600, and 800 MeV/u, and with C and Pb at 400 MeV/u have been measured using the large solid angle detector Diogene. The independence of pion multiplicity on projectile incident energy, target mass and proton multiplicity is studied in comparison with intra-nuclear cascade predictions. The discrepancy between experimental results and theory is pointed out and discussed.

A schematic drawing of the laser–microwave–laser method. The dashed arrows indicate the laser transitions between the SHF levels of the radiative decay-dominated state (n,L)=(36,34) and the Auger decay-dominated state (n,L)=(37,33) of 
. The wavy lines illustrate the microwave-induced transitions between the SSHF levels of the long-lived state.
Part of the analog delayed annihilation time spectrum (ADATS) with the two laser-stimulated annihilation peaks against the exponentially decaying background of the metastable cascade. T denotes the delay time between the two laser pulses. The photomultipliers are gated off during the initial 
 pulse arrival [14]. Thus the prompt peak is cut off and only the annihilations due to the metastable state depopulation are recorded.
Drawing of the central part of the experimental setup, a cross-section of the cryostat.
Laser resonance profile for the (n,L)=(36,34) state of 
, displaying the two laser transitions 
 between the HF states of the parent and the daughter state, at a target pressure of 250 mbar. The peaks are fitted with four Voigt functions referring to the four “allowed” E1 transitions between the SHF states of the parent state (refer to Fig. 1). The arrows indicate the corresponding theoretical transition frequencies.
Scan over the microwave frequency for two of the four SSHF transitions for the (n,L)=(36,34) state of 
, at a target pressure of 250 mbar. Each transition is fitted with Eq. (2) (solid lines). The frequencies of the measured transitions are 11.12559(14) GHz and 11.15839(18) GHz. The dashed curve shows a simulation using collision rates obtained from comparison between experiment and simulation.
First observation of two hyperfine transitions in antiprotonic 3He
  • Article
  • Full-text available

May 2011


103 Reads

We report on the first experimental results for microwave spectroscopy of the hyperfine structure of p¯3He+. Due to the helium nuclear spin, p¯3He+ has a more complex hyperfine structure than p¯4He+, which has already been studied before. Thus a comparison between theoretical calculations and the experimental results will provide a more stringent test of the three-body quantum electrodynamics (QED) theory. Two out of four super-super-hyperfine (SSHF) transition lines of the (n,L)=(36,34) state were observed. The measured frequencies of the individual transitions are 11.12559(14) GHz and 11.15839(18) GHz, less than 1 MHz higher than the current theoretical values, but still within their estimated errors. Although the experimental uncertainty for the difference of these frequencies is still very large as compared to that of theory, its measured value agrees with theoretical calculations. This difference is crucial to be determined because it is proportional to the magnetic moment of the antiproton.

Proton-proton correlations at small relative momentum in neon-nucleus collisions at E/A=400 and 800 MeV

February 1988


12 Reads

Proton-proton small angle correlations have been measured in neon-nucleus collisions, using the 4 pi detector Diogene, at 400 and 800 MeV per nucleon incident energies. Values of the size of the emitting region are obtained by comparison with the Koonin formula, taking into account the biases of the apparatus. The dependence of the density on target mass and incident energy is also analysed.

Search for projectile fragments with fractional charge in relativistic heavy ion collisions

January 1988


10 Reads

We measured the charge of about 35000 projectile fragments with Z > or = 5e produced by 14.5 GeV/nucleon and 200 GeV/nucleon 16O beams in a Pb target using CR39 plastic nuclear track detectors. A minimum track length of 3 mm in the detector without nuclear interaction was required. No evidence for fragments carrying a fractional charge was found.

OPE calculated in terms of the pole mass (left) and the 
 mass (right) of the c quark. First line: spectral densities; second line: corresponding sum-rule estimates for 
. A constant effective continuum threshold 
 is fixed in each case separately by requiring “maximal stability” of the extracted decay constant. As the result, 
 turns out to be different in the two schemes. Bold line – total result, solid line (black) – O(1) contribution; dashed line (red) – 
 contribution; dotted line (blue) – 
 contribution; dash-dotted line (green) – power contributions. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this Letter.)
Dual mass (a) and dual decay constant (b) of the D meson obtained using different Ansätze for the effective continuum threshold 
(3.2) and fixing all thresholds according to (3.3). Results for 
, and central values of the other relevant parameters are presented. (c) Dual decay constant of the D meson vs. 
 and central values of the other OPE parameters. The integer n = 0,1,2,3 is the degree of the polynomial in our Ansatz (3.2) for 
: dotted line (red) – n = 0; solid line (green) – n = 1; dashed line (blue) – n = 2; dash-dotted line (black) – n = 3. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this Letter.)
(a) Distribution of 
 obtained by the bootstrap analysis of the OPE uncertainties. Gaussian distributions for all OPE parameters but μ with corresponding errors as given in (2.1) are employed. For μ we assume a uniform distribution in the range 1 GeV < μ < 3 GeV. (b) Summary of findings for 
. Lattice results are from [10,11] for two dynamical light flavors (
) and from [12,13] for three dynamical flavors (
). The triangle represents the experimental value from PDG [14]. The estimate obtained with the constant threshold includes the OPE uncertainty only; for the τ-dependent QCD-SR result the error shown is the sum of the OPE and systematic uncertainties in (3.5), added in quadrature.
Same as Fig. 2 but for the 
(a) Distribution of 
 obtained by the bootstrap analysis of the OPE uncertainties. Gaussian distributions for all OPE parameters but μ with corresponding errors as given in (2.1) are employed. For μ we assume a uniform distribution in the range 1 GeV < μ < 3 GeV. (b) Summary of findings for 
. Lattice results are from [10,11] for two dynamical light flavors (
) and from [12,13] for three dynamical flavors (
). The triangle represents the experimental value from PDG [14]. The estimate obtained with the constant threshold includes the OPE uncertainty only; for the τ-dependent QCD-SR result the error shown is the sum of the OPE and systematic uncertainties in (3.7), added in quadrature.
OPE, charm-quark mass, and decay constants of D and D_s mesons from QCD sum rules

June 2011


83 Reads

We present a sum-rule extraction of the decay constants of the charmed mesons D and Ds from the two-point correlator of pseudoscalar currents. First, we compare the perturbative expansion for the correlator and the decay constant performed in terms of the pole and the running MS¯ masses of the charm quark. The perturbative expansion in terms of the pole mass shows no signs of convergence whereas reorganizing this very expansion in terms of the MS¯ mass leads to a distinct hierarchy of the perturbative expansion. Furthermore, the decay constants extracted from the pole-mass correlator turn out to be considerably smaller than those obtained by means of the MS¯-mass correlator. Second, making use of the OPE in terms of the MS¯ mass, we determine the decay constants of both D and Ds mesons with an emphasis on the uncertainties in these quantities related both to the input QCD parameters and to the limited accuracy of the method of sum rules.

Correlations in α-α scattering and semi-classical optical models

July 1989


20 Reads

We show the equivalence of semi-classical solutions to optical model coupled-channel equations derived from Watson's form of the nucleus-nucleus multiple-scattering series to the Glauber multiple-scattering series. A second-order solution to the semi-classical coupled-channel elastic amplitude is shown to be nearly equivalent to a second-order optical-phase-shift approximation to the Glauber amplitude if the densities of all nuclear excited states are approximated by the ground-state density. Using the Jastrow method to model the two-body density we find an average excited-state density to be of negligible importance in the double-scattering region of alpha-alpha scattering.

Energy spectrum of the kaonic 3He X-rays in coincidence with the K+K− events. The kaonic 3He 3d→2p transition is seen at 6.2 keV. Together with this peak, small peaks are seen, which are the kaonic atom X-ray lines produced by kaons stopping in the target window made of Kapton (polyimide), and the Ti Kα line at 4.5 keV.
X-ray energy spectra of the SDDs, where data of all the selected SDDs were summed: (a) data taken with the X-ray tube, and (b) data uncorrelated to the kaon production timing in the production data. The peak positions of the Ti, Cu, and Au fluorescence X-ray lines in figure (b) were used to determine the accuracy of the energy scale.
Time spectrum of the SDDs. The time difference between the K+K− coincidence and SDD X-ray hits was plotted. The peak region corresponds to the coincidence of the K+K− and X-ray events. A region from 2.9 μs to 4.6 μs was accepted as a timing window of the triple coincidences.
Timing spectrum of the two scintillators in the kaon detector. The time difference between the clock signals delivered by DAΦNE and the coincidence of the two scintillators is shown. The K+K− and MIPs coincidence events are marked in the figure. The regions marked with a rectangle were accepted as timing windows of the K+K− coincidence.
An overview of the experimental setup. The whole system was installed at the interaction point of DAΦNE.
First measurement of kaonic helium-3 X-rays

March 2011


104 Reads

The first observation of the kaonic 3He 3d - 2p transition was made using slow K- mesons stopped in a gaseous 3He target. The kaonic atom X-rays were detected with large-area silicon drift detectors using the timing information of the K+K- pairs of phi-meson decays produced by the DAFNE e+e- collider. The strong interaction shift of the kaonic 3He 2p state was determined to be -2+-2 (stat)+-4 (syst) eV.

The Power of M Theory

October 1995


17 Reads

A proposed duality between type IIB superstring theory on 9 × S1 and a conjectured 11D fundamental theory (“M theory”) on 9 × T2 is investigated. Simple heuristic reasoning leads to a consistent picture relating the various p-branes and their tensions in each theory. Identifying the M theory on 10 × S1 with type IIA superstring theory on 10, in a similar fashion, leads to various relations among the p-branes of the IIA theory.

Superalgebra b(0,1) and explicit integration of the supersymmetric Liouville equation

October 1980


9 Reads

The supersymmetric Liouville equation is integrated explicitly. The general solutions are defined by four arbitrary functions. The gauge field potentials entering the representation of zero curvature are spanned by the elements of Lie superalgebra b(0,1).

Global U(1) R-symmetry and conformal invariance of (0,2) models

June 1994


16 Reads

We derive a condition under which (0,2) linear sigma models possess a “left-moving” conformal stress tensor in cohomology (i.e. which leaves invariant the “right-moving” ground states) even away from their critical points. At the classical level this enforces quasihomogeneity of the superpotential terms. The persistence of this structure at the quantum level on the worldsheet is obstructed by an anomaly unless the charges and superpotential degrees satisfy a condition which is equivalent to the condition for the cancellation of the anomaly in a particular “right-moving” U(1) R-symmetry.

Some three generation (0,2) Calabi-Yau models

April 1995


14 Reads

It has recently been realized that a large class of Calabi-Yau models in which the VEV of the gauge connection is not set equal to the spin connection of the Calabi-Yau manifold are valid classical solutions of string theory. We provide some examples of three generation models based on such generalized Calabi-Yau compactifications, including models with observable gauge group SU (3) × SU (2) × U (1).

(a) A hypothetical universe with all galaxies having the same handedness. Note that galaxies in one hemisphere would appear to us to be right-handed and in the opposite hemisphere left-handed. (b) A “typical” spiral galaxy from the SDSS. This one is defined as having right-handed “spin”. (c) A left-handed two-armed spiral galaxy.
Polar plot of net asymmetries 〈A〉 in 30° sectors in right ascension and slices in z. Segments with positive 〈A〉 are indicated in red and negative 〈A〉 in blue. The 〈A〉 for segments with <10 galaxies are not shown. The larger numbers near the periphery give the overall asymmetry for that sector; the black numbers in parentheses are the total number of spiral galaxies in the sector. The NGP is the north pole of our Galaxy, so that the left half of the plot corresponds roughly to the northern Galactic hemisphere. The black arrow shows the most probable dipole axis. Declinations between −19° and +60° were used.
(a) Spatial correlation of the spiral galaxies in the sample vs. 3D separation. The peaking for separations <20 Mpc/h is due to clustering. (b) The asymmetry of spiral galaxy spins vs. separation. The correlation extends out to separations ∼210 Mpc/h.
Variation of χ2–dof with αA for δA=32°. The xʼs are for axes at 90° to the best-fit axis.
Probability of obtaining a particular value of (dof–χmin2) for 4×105 samples of the 15,158 galaxies with randomized handednesses. The lowest χ2 from 100 axes randomly chosen within the SDSS survey was used. The arrow shows the value of χ2=13.356 for the actual handedness assignments for the best-fit axis at (αA,δA)=(217°,32°); the probability of finding that value or greater by chance is 7.9×10−4.
Detection of a Dipole in the Handedness of Spiral Galaxies with Redshifts z ~ 0.04

April 2011


243 Reads

A preference for spiral galaxies in one sector of the sky to be left-handed or right-handed spirals would indicate a parity violating asymmetry in the overall universe and a preferred axis. This study uses 15158 spiral galaxies with redshifts <0.085 from the Sloan Digital Sky Survey. An unbinned analysis for a dipole component that made no prior assumptions for the dipole axis gives a dipole asymmetry of -0.0408\pm0.011 with a probability of occurring by chance of 7.9 x 10-4. A similar asymmetry is seen in the Southern Galaxy spin catalog of Iye and Sugai. The axis of the dipole asymmetry lies at approx. (l, b) =(52{\deg}, 68.5{\deg}), roughly along that of our Galaxy and close to alignments observed in the WMAP cosmic microwave background distributions. The observed spin correlation extends out to separations ~210 Mpc/h, while spirals with separations < 20 Mpc/h have smaller spin correlations.

FIG. 3: Generalized forward spin polarizability γ p 0 as a function of Q 2 for the full integral (closed circles), the measured portion of the integral (open circles) and Q 2 = 0 [44] (triangle). The systematic error on the measured (grey) and unmeasured (dark) contributions are indicated by bands. χPT calculations [17, 45] are shown along with MAID 2003 [46]. The data shown on the right are weighted by Q 6 /(16αM 2 ). Our parametrization of world data is also shown at moderate to high Q 2 .
Moments of the spin structure functions and for 0.05<Q2<3.0 GeV2

February 2009


77 Reads

The spin structure functions g1 for the proton and the deuteron have been measured over a wide kinematic range in x and Q2 using 1.6 and 5.7 GeV longitudinally polarized electrons incident upon polarized NH3 and ND3 targets at Jefferson Lab. Scattered electrons were detected in the CEBAF Large Acceptance Spectrometer, for 0.05<Q2<5 GeV2 and W<3 GeV. The first moments of g1 for the proton and deuteron are presented – both have a negative slope at low Q2, as predicted by the extended Gerasimov–Drell–Hearn sum rule. The first extraction of the generalized forward spin polarizability of the proton is also reported. This quantity shows strong Q2 dependence at low Q2. Our analysis of the Q2 evolution of the first moment of g1 shows agreement in leading order with Heavy Baryon Chiral Perturbation Theory. However, a significant discrepancy is observed between the data and Chiral Perturbation calculations for , even at the lowest Q2.

Measurement of the pion form factor in the time-like region for q2 values between 0.1 (GeV/c)2 and 0.18 (GeV/c)2

April 1984


30 Reads

The EM form factor of the pion has been studied in the time-like region by measuring σ(e+e− → π+π−) normalized to σ(e+e− → μ+μ−). Results have been obtained for q2 down to the physical threshold.

Coherent π0 threshold production from the deuteron at Q2=0.1 GeV2/c2

February 2001


51 Reads

First data on coherent threshold π0 electroproduction from the deuteron taken by the A1 Collaboration at the Mainz Microtron MAMI are presented. At a four-momentum transfer of the full solid angle was covered up to a center-of-mass energy of 4 MeV above threshold. By means of a Rosenbluth separation the longitudinal threshold s wave multipole and an upper limit for the transverse threshold s wave multipole could be extracted and compared to predictions of Heavy Baryon Chiral Perturbation Theory.

Charged particle multiplicity correlations in pp̄ collisions at s=0.3−1.8 TeV

June 1995


13 Reads

The correlations between charged particle multiplicitie produced in forward and backward pseudorapidity regions in pp̄ interactions have been measured with a 240 element scintillator hodoscope. The correlation coefficient and the variance of the difference of multiplicities in the two pseudorapidity regions were deterermined for . These results have been interpreted in terms of a cluster model of particle production.

Figure 1: Galaxy images (left) and the transforma- 
Figure 2: The peaks detected in the radial intensity 
Figure 4: Galaxy handedness asymmetry in different RA ranges
Handedness asymmetry of spiral galaxies with z<0.3 shows cosmic parity violation and a dipole axis

July 2012


355 Reads

A dataset of 126,501 spiral galaxies taken from Sloan Digital Sky Survey was used to analyze the large-scale galaxy handedness in different regions of the local universe. The analysis was automated by using a transformation of the galaxy images to their radial intensity plots, which allows automatic analysis of the galaxy spin and can therefore be used to analyze a large galaxy dataset. The results show that the local universe (z<0.3) is not isotropic in terms of galaxy spin, with probability P<5.8*10^-6 of such asymmetry to occur by chance. The handedness asymmetries exhibit an approximate cosine dependence, and the most likely dipole axis was found at RA=132, DEC=32 with 1 sigma error range of 107 to 179 degrees for the RA. The probability of such axis to occur by chance is P<1.95*10^-5 . The amplitude of the handedness asymmetry reported in this paper is generally in agreement with Longo, but the statistical significance is improved by a factor of 40, and the direction of the axis disagrees somewhat.

First underground results with NEWAGE-0.3a direction-sensitive dark matter detector

February 2010


41 Reads

A direction-sensitive dark matter search experiment at Kamioka underground laboratory with the NEWAGE-0.3a detector was performed. The NEWAGE- 0.3a detector is a gaseous micro-time-projection chamber filled with CF4 gas at 152 Torr. The fiducial volume and target mass are 20*25*31 cm3 and 0.0115 kg, respectively. With an exposure of 0.524 kgdays, improved spin-dependent weakly interacting massive particle (WIMP)-proton cross section limits by a direction-sensitive method were achieved including a new record of 5400 pb for 150 GeV/c2 WIMPs. We studied the remaining background and found that ambient gamma-rays contributed about one-fifth of the remaining background and radioactive contaminants inside the gas chamber contributed the rest.

Complex fragment emission from the 3He+natAg system between 0.48 and 3.6 GeV

August 1990


7 Reads

The emission of complex fragments (3⩽Z≲12) from reactions of 3He with natAg has been studied at bombarding energies of E = 480, 900, 1800, 2700 and 3600 MeV. Between 900 and 1800 MeV slopes of the fragment kinetic energy spectra at backward angles undergo a change in character, becoming much flatter; in addition, the Coulomb peak is found to broaden significantly and shift to lower energies. Power-law fits to the fragment charge distributions result in decreasing values of the exponent τ up to a bombarding energy of 1800 MeV; at this value and beyond, a constant value of τ=2.1±0.1 is observed. Elemental cross sections at the highest energy are found to increase by approximately two orders of magnitude relative to data near 100 MeV. The data suggest a change in reaction mechanism between incident energies of 900 and 1800 MeV.

Measurement of the spin dependent neutron-proton total cross section differences ΔσT and ΔσL between 0.63 and 1.08 GeV

April 1987


23 Reads

We present first measurements of total cross section differences ΔσT and ΔσL for a polarized neutron beam transmitted through a polarized proton target. Measurements were carried out at SATURNE II, at 0.63, 0.88, 0.98 and 1.08 GeV. The results are compared with ΔσL data points deduced from p-d and p-p transmission experiments, and with phase shift analyses predictions. The present results together with the corresponding pp data yield two of the three spin dependent forward scattering amplitudes for isospin I=0.

Measurement of the bottom quark production cross section in proton-antiproton collisions at √s = 0.63 TeV

October 1988


22 Reads

We summarize the results obtained in the UA1 experiment on the production of bottom quarks in proton-antiproton collisions at √s=0.63 TeV. Independent muon data samples are used to determine the bottom quark production cross section in different transverse momentum ranges from 6 to 30 GeV. A recent theoretical calculation to O(αs3) of the inclusive bottom quark transverse momentum spectrum in hadronic collisions shows reasonable agreement with the data. We extrapolate the integral PT distribution to PT=0 and in rapidity to estimate the total cross section forthe production of bottom quark pairs. Assuming the shape in PT and rapidity given by the O(αs3) calcultaion, we obtain .

A search for oscillations of muon neutrinos in an experiment with L/E ≅0.7 km/GeV

July 1984


10 Reads

A low-energy muon neutrino beam was used to illuminate two similar fine-grained neutrino detectors placed at 123 m and 903 m from the beginning of the neutrino source. The fiducial masses of the “close” and the “far” detector were about 36 tons and 120 tons respectively. The average energy of the selected neutrino events was 1.5 GeV. Data were recorded for an integrated flux of about 1019 protons. Quasielastic charged current events initiated by νe's have been searched for and an upper limit of 2.7%, at 90% confidence level, is obtained for the fraction of νμ's transformed into νe's. For complete mixing this correspnds to a limit Δm2 ⩽ 0.20 eV2 for the transition νμ → νe and to a minimum value of the mixing parameter sin22θ = 0.04. In the same data sample we compared the rates in the two detectors of νμ-initiated charged current events, mainly of quasielastic type: we conclude that oscillations of νμ's to ντ's, and possibly heavier neutrinos, do not appear. For complete mixing the limit in this case is Δm2 ⩽ 0.29 eV2.

Elastic differential cross sections and analyzing powers for +40,42,44,48Ca at 0.8 GeV

February 1979


11 Reads

Differential cross sections and analyzing powers for the elastic scattering of 800 MeV polarized protons from 40,42,44,48Ca are reported. A first-order, spin-dependent KMT optical potential analysis is presented from which the rms radii of the neutron densities are deduced. A comparison of these results with other determinations and with various theoretical predictions is given.

η production in 40Ca+40Ca reactions between 0.8 and 2 GeV/A

November 1991


5 Reads

We present results of the first nonperturbative calculation of η-meson production in heavy-ion collisions from 0.8 to 2 GeV/u bombarding energy. In this calculation mean-field effects as well as the dynamic population of nucleon resonances and their decay are taken into account. The results obtained are compared with very recent experiments at 1 GeV/u and are analyzed with respect to the time development of the hadronic composition of the reaction volume.

Left: Differential cross section for e+e−→π+π−γ, with 50°<θγ<130°. Right: bare cross section σππbare for e+e−→π+π−. Data points have statistical error attached, the gray band gives the statistical and systematic uncertainty (added in quadrature).
Left: MC signal and background distributions in the Mtrk–Mππ2 plane. Right: the same, in the Ω–Mππ2 plane. Black lines indicate the cuts described in the text.
Vertical cross section in the y–z plane of the KLOE detector, showing the small and large angle regions for photons and pions used in the different KLOE measurements.
Top left: |Fπ|2 from CMD-2 [30,31], SND [32] and the present KLOE result as function of (Mππ0)2. Bottom left: Fractional difference between CMD-2 or SND and KLOE. Top right: σππbare from BaBar [36] and the new KLOE result as function of Mππ0. Bottom right: Fractional difference between BaBar and KLOE. CMD-2, SND and BaBar data points have the total uncertainty attached. The dark (light) band in the lower plots shows statistical (total) error of the KLOE result.
Comparison of the present result, KLOE10, with the previous KLOE result, KLOE08 [7]. Left: Pion form factor |Fπ|2. Right: Fractional difference between KLOE08 and KLOE10 results. The dark (light) gray band gives the statistical (total) error for the present result. Errors on KLOE08 points contain the combined statistical and systematic uncertainty.
Measurement of σ(e+e-→Π+ΠΠ-) from threshold to 0.85 GeV2 using initial state radiation with the KLOE detector

June 2010


128 Reads

We have measured the cross section of the radiative process e+e- -> pi+pi-gamma with the KLOE detector at the Frascati phi-factory DAPHNE, from events taken at a CM energy W=1 GeV. Initial state radiation allows us to obtain the cross section for e+e- -> pi+pi-, the pion form factor |F_pi|^2 and the dipion contribution to the muon magnetic moment anomaly, Delta a_mu^{pipi} = (478.5+-2.0_{stat}+-5.0_{syst}+-4.5_{th}) x 10^{-10} in the range 0.1 < M_{pipi}^2 < 0.85 GeV^2, where the theoretical error includes a SU(3) ChPT estimate of the uncertainty on photon radiation from the final pions. The discrepancy between the Standard Model evaluation of a_mu and the value measured by the Muon g-2 collaboration at BNL is confirmed.

Polarization in K+n charge exchange scattering between 0.851 GeV/c and 1.351 GeV/c

September 1980


7 Reads

The polarization parameter for K+n charge exchange scattering has been measured at five momenta between 0.851 GeV/c and 1.351 GeV/c for centre of mass angles . Results from a phase shift analysis incorporating these results are presented. No Z∗ resonances are observed.

Fig. 2: Reconstructed π 0 peak width (a) and position (b) as a function of p t in pp collisions at √ s = 7 TeV in PHOS and in the photon conversion method (PCM) compared to Monte Carlo simulations. The horizontal line in (b) indicates the nominal π 0 mass. 
Fig. 3: a) Differential invariant cross section of π 0 production in pp collisions at √ s = 7 TeV (circles) and 0.9 TeV (squares) and of η meson production at √ s = 7 TeV (stars). The lines and the boxes represent the statistical and systematic error of the combined measurement respectively. The uncertainty on the pp cross section is not included. NLO pQCD calculations using the CTEQ6M5 PDF and the DSS (AESS for η mesons) FF for three scales µ = 0.5p t , 1p t and 2p t are shown. Dotted lines in panels b) and c) correspond to the ratios using the BKK FF. Ratio of the NLO calculations to the data parametrisations are shown in panels b), c) and d). The full boxes represent the uncertainty on the pp cross sections. 
Fig. 4: Ratio of the two independent π 0 meson measurements to the fit of the combined normalized invariant production cross section of π 0 mesons in pp collisions at √ s = 7 TeV. 
Fig. 5: η/π 0 ratio measured in pp collisions at √ s = 7 TeV compared to NLO pQCD predictions. 
Neutral pion and $\eta$ meson production in proton-proton collisions at $\sqrt{s}=0.9$ TeV and $\sqrt{s}=7$ TeV

May 2012


114 Reads

The first measurements of the invariant differential cross sections of inclusive $\pi^0$ and $\eta$ meson production at mid-rapidity in proton-proton collisions at $\sqrt{s}=0.9$ TeV and $\sqrt{s}=7$ TeV are reported. The $\pi^0$ measurement covers the ranges $0.4<p_T<7$ GeV/$c$ and $0.3<p_T<25$ GeV/$c$ for these two energies, respectively. The production of $\eta$ mesons was measured at $\sqrt{s}=7$ TeV in the range $0.4<p_T<15$ GeV/$c$. Next-to-Leading Order perturbative QCD calculations, which are consistent with the $\pi^0$ spectrum at $\sqrt{s}=0.9$ TeV, overestimate those of $\pi^0$ and $\eta$ mesons at $\sqrt{s}=7$ TeV, but agree with the measured $\eta/\pi^0$ ratio at $\sqrt{s}=7$ TeV.

K-matrix analysis of the (IJPC = 00++) amplitude in the mass region up to 1550 MeV

August 1996


17 Reads

K-matrix analysis of the 00++ wave is performed in the channels ππ, , ηη and 4π in the mass region up to 1550 MeV. The fit is based on the following data: [V.V. Anisovich et al., Phys. Lett. B 323 (1994) 233; C. Amsler et al., Phys. Lett. B 333 (1994) 277; B 342 (1995) 433], πN → ππN [B. Hyams et al., Nucl. Phys. B 64 (1973) 134; A.A. Kondashov et al., Proc. 27th Intern. Conf. on High Energy Physics, Glasgow (1994) 1407; Yu.D. Prokoshkin et al., Physics-Doklady (1995), in press; D. Alde et al., Study of the f0(995) resonance in the π0π0 decay channel, Preprint CERN-PPE/94-157, 1994], [S.J. Lindenbaum and R.S. Longacre, Phys. Lett. B 274 (1992) 492; A. Etkin et al., Phys. Rev. D 25 (1982) 1786] and the inelastic cross section of the ππ interaction [M. Alston-Garnjost et al., Phys. Lett. B 36 (1971) 152]. Simultaneous analysis of these data confirms the existence of the scalar resonances: f0(980), f0(1300) and f0(1500), the poles of the amplitude being at the following complex masses (in MeV): (1008 ± 10) − i(43 ± 5), (1290 ± 25) − i(120 ± 15), and (1497 − 6) − i(61 ± 5). The fourth pole has sunk deeply into the complex plane: (1430 ± 150) − i(600 ± 100). Positions of the K-matrix poles (which are referred to the masses of bare states) are at 750 ± 120 MeV, 1240 ± 30 MeV, 1280 ± 30 MeV and 1615 ± 40 MeV. Coupling constants of the K-matrix poles to the ππ, ηη and channels are found that allow us to analyze the quark and gluonic content of bare states. It is shown that f0bare(1240) and f0bare(1615) (which are strongly related to f0(1500)) can be considered as good candidates for scalar glueball.

HRI-P-07-07-002 Distinguishing the Littlest Higgs model with T-parity from supersymmetry at the LHC using trileptons

September 2007


36 Reads

We analyse hadronically quiet trilepton signatures in the T-parity conserving Littlest Higgs model and in R-parity conserving supersymmetry at the Large Hadron Collider. We identify the regions of the parameter space where such signals can reveal the presence of these new physics models above the Standard Model background and distinguish them from each other, even in a situation when the mass spectrum of the Littlest Higgs model resembles the supersymmetric pattern.

HRI-P-08-11-004 Hybrid textures in minimal seesaw mass matrices

November 2008


57 Reads

In the context of minimal seesaw framework, we study the implications of Dirac and Majorana mass matrices in which two rigid properties coexist, namely, equalities among mass matrix elements and texture zeros. In the first part of the study, we discuss general possibilities of the Dirac and Majorana mass matrices for neutrinos with such hybrid structures. We then classify the mass matrices into realistic textures which are compatible with global neutrino oscillation data and unrealistic ones which do not comply with the data. Among the large number of general possibilities, we find that only 6 patterns are consistent with the observations at the level of the most minimal number of free parameters. These solutions have only 2 adjustable parameters, so that all the mixing angles can be described in terms of the two mass differences or pure numbers. We analyze these textures in detail and discuss their impacts for future neutrino experiments and for leptogenesis. Comment: 25 pages, 2 figures; (ver. 2) A significant revision is made for easy reading, and analyses on CP violation are added

SOGANG-MP 01/07 Entropy of the Schwarzschild black hole to all orders in the Planck length

August 2007


37 Reads

Considering corrections to all orders in the Planck length on the quantum state density from a generalized uncertainty principle (GUP), we calculate the statistical entropy of the scalar field on the background of the Schwarzschild black hole without any cutoff. We obtain the entropy of the massive scalar field proportional to the horizon area.

The “background with spectrum hardening + pulsars + dark matter annihilation into e+e−” model for the second set of electron/positron data. Top panel: the fit of the Fermi-LAT long path electron/positron total spectrum [7], the updated Fermi-LAT electron/positron total spectrum in the energy range 20–200 GeV [9], and the PAMELA electron spectrum data [28]. Bottom panel: the fit of the AMS-02 positron fraction data. The best fit parameters are presented in Table 2 (i.e., scenario (e)). The existence of dark matter particles with a rest mass ∼100 GeV and 〈σv〉χχ→e+e−∼5.5×10−27 cm3s−1 cannot be ruled out by current data.
The regions of parameter space (68.3% and 99.5% confidence levels) which provide a reasonable fit to the second set of data comparing with the bounds set by Fermi-LAT Galactic diffuse emission (adopted from [29], the short-dashed line represents the upper limits on 〈σv〉 found in the analysis with no model of the astrophysical background, while the solid line is the bound found in the analysis with a modeling of the background) and by the extra-galactic diffuse emission (adopted from [23], the long-dashed line in the bottom panel). Top panel is for the annihilation channel χχ→μ+μ− and the isothermal-sphere like dark matter distribution model is adopted. Bottom panel is for the decay channel χ→μ+μ− and the NFW dark matter distribution model is adopted. In this work we do not present the cases of annihilation/decay into τ+τ− since they have been excluded by the γ-ray observations.
The upper two panels: the “background with spectrum hardening + dark matter annihilation into μ+μ−” model for the second set of electron/positron data. The lower panels: the “background with spectrum hardening + dark matter decay into μ+μ−” model for the second set of electron/positron data. The best fit parameters are summarized in Table 2.
AMS-02 positron excess: New bounds on dark matter models and hint for primary electron spectrum hardening

March 2013


213 Reads

The data collected by ATIC, CREAM and PAMELA all display remarkable cosmic-ray-nuclei spectrum hardening above the magnetic rigidity $\sim$ 240 GV. One natural speculation is that the primary electron spectrum also gets hardened (possibly at $\sim 80$ GV) and the hardening partly accounts for the electron/positron total spectrum excess discovered by ATIC, HESS and Fermi-LAT. If it is the case, the increasing behavior of the subsequent positron-to-electron ratio will get flattened and the spectrum hardening should be taken into account in the joint fit of the electron/psoitron data otherwise the inferred parameters will be biased. Our joint fits to the latest AMS-02 positron fraction data together with the PAMELA/Fermi-LAT electron/positron spectrum data suggest that the primary electron spectrum hardening is needed in most though not all modelings. The bounds on dark matter models have also been investigated. In the presence of spectrum hardening of primary electrons, the amount of dark-matter-originated electron/positron pairs needed in the modeling is smaller. Even with such a modification, the annihilation channel $\chi\chi \rightarrow \mu^{+}\mu^{-}$ has been tightly constrained by the Fermi-LAT Galactic diffuse emission data. The decay channel $\chi\rightarrow \mu^{+}\mu^{-}$ is found to be viable.

FIG. 1: Proton spectrum derived through fitting PAMELA and CREAM data. References of the proton data: AMS [44], BESS [45], ATIC2 [17], PAMELA [18] and CREAM [19]. 
FIG. 5: Expected total fluxes of the pure electrons for the three fits corresponding to Figs. 2-4. 
FIG. 8: 1σ and 2σ parameter regions on the mχ − σv plane for the DM annihilation scenario. The lines show the 95% upper limit of Fermi γ-ray observations of the Galactic center (thin lines, with different normalization of the local density corrected, [50]) and dwarf galaxies (thick lines, [51]) for µ + µ − (black solid) and τ + τ − (blue dashed-dotted) channels respectively. 
Reconcile the AMS-02 positron fraction and Fermi-LAT/HESS total spectra by the primary electron spectrum hardening

April 2013


123 Reads

The recently reported positron fraction up to $\sim 350$ GeV by AMS-02 seems to have tension with the total electron/positron spectra detected by Fermi and HESS, for either pulsar or dark matter annihilation/decay scenario as the primary positron sources. In this work we will show that the tension will be removed by an adjustment of the primary electron spectrum. If the primary electron spectrum becomes harder above $\sim50$ GeV, similar as the cosmic ray nuclei spectrum, the AMS-02 positron fraction and Fermi/HESS data can be well fitted by both the pulsar and dark matter models. This result indicates that there should be a common origin of the cosmic ray nuclei and the primary electrons. Furthermore, this study also implies that the properties of the extra sources derived from the fitting to the AMS-02 data should depend on the form of background.

Thermally averaged dark matter annihilation cross section at the current Universe as a function of ϵ in the lower horizontal axis, as required by the observed relic density. The upper horizontal axis gives the corresponding value of λ4.
Spectra of the positron flux (left) and the ratio of antiproton-to-proton fluxes (right) in comparison with those observed by AMS-02 from cosmic rays, drawn in thick curves. Red solid curves are used for MIN, dashed green curves for MED, and dash-dotted blue curves for MAX. Also indicated are the values of ϵ in the left plot and vΔ in the right plot. The background in the left plot is given by the purple dotted curve, and those in the right plot are given by the thin curves.
Dark matter for excess of AMS-02 positrons and antiprotons

April 2015


182 Reads

We propose a dark matter explanation to simultaneously account for the excess of antiproton-to-proton and positron power spectra observed in the AMS-02 experiment while having the right dark matter relic abundance and satisfying the current direct search bounds. We extend the Higgs triplet model with a hidden gauge symmetry of $SU(2)_X$ that is broken to $Z_3$ by a quadruplet scalar field, rendering the associated gauge bosons stable weakly-interacting massive particle dark matter candidates. By coupling the complex Higgs triplet and the $SU(2)_X$ quadruplet, the dark matter candidates can annihilate into triplet Higgs bosons each of which in turn decays into lepton or gauge boson final states. Such a mechanism gives rise to correct excess of positrons and antiprotons with an appropriate choice of the triplet vacuum expectation value. Besides, the model provides a link between neutrino mass and dark matter phenomenology.

MIFP-09-02 Extremal Static AdS Black Hole/CFT Correspondence in Gauged Supergravities

February 2009


27 Reads

A recently proposed holographic duality allows the Bekenstein–Hawking entropy of extremal rotating black holes to be calculated microscopically, by applying the Cardy formula to the two-dimensional chiral CFTs associated with certain reparameterisations of azimuthal angular coordinates in the solutions. The central charges are proportional to the angular momenta of the black hole, and so the method degenerates in the case of static (non-rotating) black holes. We show that the method can be extended to encompass such charged static extremal AdS black holes by using consistent Kaluza–Klein sphere reduction ansatze to lift them to exact solutions in the low-energy limits of string theory or M-theory, where the electric charges become reinterpreted as angular momenta associated with internal rotations in the reduction sphere. We illustrate the procedure for the examples of extremal charged static AdS black holes in four, five, six and seven dimensions.

Upper three panels: Contour lines of 68th, 95th, and 99th percentile of the likelihood function (the chi-squared distribution) for the wino decays through the interactions L1L2Eic (top-left panel), L3L1Eic (top-right panel), and L3L2Eic (middle-left panel), where i=1,2, and 3. See text for gray and yellow shaded regions. Lower three panels: The positron fraction (middle-right panel), the electron flux (bottom-left panel), and the positron flux (bottom-right panel) with the latest AMS-02 data for the decay through the interaction L3L1E2c. See text for red solid lines and red shaded regions. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
Mass of decaying wino from AMS-02 2014

September 2014


38 Reads

We revisit the decaying wino dark matter scenario in the light of the updated positron fraction, electron and positron fluxes in cosmic ray recently reported by the AMS-02 collaboration. We show the AMS-02 results favor the mass of the wino dark matter at around a few TeV, which is consistent with the prediction on the wino mass in the pure gravity mediation model.

Channel coupling and distortion effects in the excitation of the 02+ state in 12C by alpha scattering

May 1984

The excitation of the 02+ (7.65 MeV) state in 12C by inelastic alpha scattering is investigated using microscopic resonating group wave functions in a coupled channel folding model. The importance of coupling to other states and the influence of varying the optical potential in the excited states is studied. Both effects must be taken into account for a quantitative description.

Fig. 3. Iso-m DM contours in Scenario I, with r L = r Q = 0 and μ L = μ Q (left), and Scenario II, with μ L = r Q = 0 (right), that give Ω DM h 2 = 0.11. The green shaded regions are allowed at the 95% C.L. by resonance searches at the LHC, and the blue shaded regions are compatible with antiproton data.
Iso-mDM contours in Scenario I, with rL=rQ=0 and μL≠μQ (left), and Scenario II, with μL=rQ=0 (right), that give ΩDMh2=0.11. The green shaded regions are allowed at the 95% C.L. by resonance searches at the LHC, and the blue shaded regions are compatible with antiproton data.
Left: Fits to AMS-02 e− and e+ spectra for different leptonic branching fractions, for a 1 TeV KK photon. Variations in the galactic e± background and boost factor are marginalized over for each point. Middle: 3σ bounds on BRH/BRL from the AMS-02 e± spectra and the PAMELA antiproton spectrum. Right: The shaded region shows the p¯ signal + background spectra for mDM=1 TeV that correspond to the 3σ fit to AMS-02. The DM-only contributions (black dashed) are higher than the PAMELA data, even without considering the galactic background. The separation between the polynomial fit to the p¯ data (gray dotted) and an extreme possibility for the background (labeled “Bkg”) gives an idea of the size of the deviation permitted by our modeling of the background uncertainty.
e± (solid) and antiproton (dotted) injection spectra from leptonic (blue) and hadronic (red) annihilation channels, with BRL=0.4 and BRH=0.6. The end-point peak is due to DM annihilation into e+e−. The DM mass is 1 TeV.
AMS-02 and Next-to-Minimal Universal Extra Dimensions

February 2014


61 Reads

The anomaly detected by AMS-02 and PAMELA in the cosmic-ray positron flux when interpreted as arising from dark matter annihilation suggests that dark matter may interact differently with hadrons and leptons so as to remain compatible with cosmic-ray antiproton data. Such a scenario is readily accommodated in models with extra spatial dimensions. We study indirect detection of Kaluza-Klein (KK) dark matter in Universal Extra Dimensions with brane-localized terms and fermion bulk masses: Next-to-Minimal Universal Extra Dimensions. So that an excess of antiprotons is not produced in explaining the positron anomaly, it is necessary that the KK bulk masses in the lepton and hadron sectors be distinct. Even so, we find that cosmic-ray data disfavor a heavy KK photon dark matter scenario. Also, we find these scenarios with flavor-universal bulk masses to be in conflict with dijet and dilepton searches at the LHC.

IISc-CHEP/03/09 Use of transverse beam polarization to probe anomalous V V H interactions at a Linear Collider

September 2009


32 Reads

We investigate use of transverse beam polarization in probing anomalous coupling of a Higgs boson to a pair of vector bosons, at the International Linear Collider (ILC). We consider the most general form of VVH (V=W/Z) vertex consistent with Lorentz invariance and investigate its effects on the process , f being a light fermion. Constructing observables with definite CP and naive time reversal () transformation properties, we find that transverse beam polarization helps us to improve on the sensitivity of one part of the anomalous ZZH coupling that is odd under CP. Even more importantly it provides the possibility of discriminating from each other, two terms in the general ZZH vertex, both of which are even under CP and . Use of transverse beam polarization when combined with information from unpolarized and linearly polarized beams therefore, allows one to have completely independent probes of all the different parts of a general ZZH vertex.

ADP-09-03/T681 The strong coupling and its running to four loops in a minimal MOM scheme

November 2009


32 Reads

We introduce the minimal momentum subtraction (MiniMOM) scheme for QCD. Its definition allows the strong coupling to be fixed solely through a determination of the gluon and ghost propagators. In Landau gauge this scheme has been implicit in the early studies of these propagators, especially in relation to their non-perturbative behaviour in the infrared and the associated infrared fixed-point. Here we concentrate on its perturbative use. We give the explicit perturbative definition of the scheme and the relation of its β-function and running coupling to the scheme up to 4-loop order in general covariant gauges. We also demonstrate, by considering a selection of Nf=3 examples, that the apparent convergence of the relevant perturbative series can in some (though not all) cases be significantly improved by re-expanding the coupling version of this series in terms of the MiniMOM coupling, making the MiniMOM coupling also of potential interest in certain phenomenological applications.

TIFR/TH/09-04 Modification of Gravitational Anomaly Method in Hawking Radiation

June 2009


43 Reads

We discuss an ambiguity of the derivation of the Hawking radiation through the gravitational anomaly method and propose modifications of this method such that it reproduces the correct thermal fluxes. In this modified gravitational anomaly method, we employ the two-dimensional conformal field theory technique.

Feynman graphs for the RPV contributions to the process e+e−→fkf¯k, where f stands for any fermion in the SM and j,k represent the generation index.
The normalized differential cross-section for the R-parity violating contribution as a function of the azimuthal angle for different values of sneutrino mass. The coupling constants are chosen for each sneutrino mass to saturate the experimental bounds, as discussed in the text. Also shown in solid lines is the SM expectation.
The asymmetry AQ in the azimuthal distribution for t-channel exchange of squark as a function of the squark mass exchanged for the maximum allowed value of λ for that squark mass for integrated luminosities L=500, 1000 fb−1. Also shown are the SM expectation and discovery limits at 1σ, 2σ and 3σ levels.
The asymmetry A as defined by Eq. (10) for the signal as a function of the sneutrino mass for integrated luminosities L=500, 1000 fb−1 and for the maximum value of the product of RPV couplings λ211λ233′ for that sneutrino mass. Also shown are the SM expectation and discovery limits at 1σ, 2σ and 3σ levels.
The normalized differential cross-section for the R-parity violating contribution as a function of the azimuthal angle for t-channel exchange of a squark of mass 400 GeV. Also shown in solid lines is the SM expectation.
HIP-2009-04/TH Use of Transverse polarization to probe R-parity violating supersymmetry at ILC.

March 2009


42 Reads

In supersymmetric theories with R-parity violation, squarks and sleptons can mediate Standard Model fermion–fermion scattering processes. These scalar exchanges in e+e− initiated reactions can give new signals at future linear colliders. We explore use of transverse beam polarization in the study of these signals in the process . We highlight certain asymmetries, which can be constructed due to the existence of the transverse beam polarization, which offer discrimination from the Standard Model (SM) background and provide increased sensitivity to the R-parity violating couplings.

OUTP-09-05P Hybrid natural inflation from non Abelian discrete symmetry

February 2010


24 Reads

A spontaneously broken global discrete symmetry may have pseudo Goldstone modes associated with the spontaneous breaking of the approximate continuous symmetry of the low dimension terms in the Lagrangian. These provide natural candidates for an inflaton that can generate slow-roll inflation. We show that, in the case of a non-Abelian discrete symmetry, the pseudo Goldstone modes readily couple to further scalar fields in a manner that the end of inflation is determined by these additional scalar fields, generating hybrid inflation. We give a simple parameterisation of the inflationary potential in this case, determine the inflationary parameters resulting, and show that phenomenological successful inflation is possible while keeping the scale of symmetry breaking sub-Planckian. Unlike natural inflation the inflation scale can be very low. We construct two simple hybrid inflation models, one non-supersymmetric and one supersymmetric. In the latter case no parameters need be chosen anomalously small.

Parity-non-conserving internucleon potentials studied in the 113Cd (n, γ) 114Cd reaction 0679

August 1967


7 Reads

The asymmetry in the γ intensity after capture of polarized neutrons in 113Cd was investigated. An upper limit to a possible asymmetry A was determined of ∣A∣ < 4.7 × 10−4. This result does not agree with that of Abov et al.

FERMILAB-PUB-07-459-T Massive color-octet bosons and pairs of resonances at hadron colliders

December 2008


26 Reads

We analyze collider signatures of massive color-octet bosons whose couplings to quarks are suppressed. Gauge invariance forces the octets to couple at tree level only in pairs to gluons, with a strength set by the QCD gauge coupling. For a spin-1 octet, the cross section for pair production at hadron colliders is larger than that for a quark of equal mass. The octet decays into two jets, leading to a 4-jet signature with two pairs of jets forming resonances of the same mass. For a spin-0 octet the cross section is smaller, and the dominant decay is into , or if kinematically allowed. We estimate that discovery of spin-1 octets is possible for masses up to 330 GeV at the Tevatron, and 1 TeV at the LHC with 1 fb−1, while the reach is somewhat lower for spin-0 octets.

BA-07-31 Window For Higgs Boson Mass From Gauge-Higgs Unification

January 2008


24 Reads

We consider six-dimensional gauge models compactified on the orbifold T2/ZN (N=2,3,4,6) such that the Standard Model (SM) Higgs doublet arises from the extra-dimensional components of the gauge field. For , where Λ denotes the compactification scale, we obtain for the SM Higgs boson mass. We also consider gauge-Higgs-top and gauge-Higgs-bottom Yukawa unification which respectively yield and for a top quark pole mass . As a special case we recover the result previously obtained for five-dimensional models.

BA-07-23 Higgs Boson Mass From Gauge-Higgs Unification

June 2007


20 Reads

In certain five-dimensional gauge theories the Standard Model Higgs doublet is identified, after compactification on the orbifold S1/Z2, with the zero mode of the fifth component of the gauge field. An effective potential for the Higgs field is generated via quantum corrections, triggered by the breaking of the underlying gauge symmetry through boundary conditions. The quartic Higgs coupling can be estimated at low energies by employing the boundary condition that it vanishes at the compactification scale Λ, as required by five-dimensional gauge invariance. For Λ≳1013–1014 GeV, the Standard Model Higgs boson mass is found to be mH=125±4 GeV, corresponding to a top quark pole mass Mt=170.9±1.8 GeV. A more complete (gauge-Higgs–Yukawa) unification can be realized for Λ∼108 GeV, which happens to be the scale at which the SU(2) weak coupling and the top quark Yukawa coupling have the same value. For this case, mH=117±4 GeV.

BA-07-23 Testing Spontaneous Parity Violation at the LHC

March 2008


31 Reads

We construct a supersymmetric SUL(2)×SUR(2)×U(1)B−L model in which a discrete symmetry (C-parity) implements strict left–right symmetry in the scalar (Higgs) sector. Although two electroweak bidoublets are introduced to accommodate the observed fermion masses and mixings, a natural missing partner mechanism insures that a single pair of MSSM Higgs doublets survives below the left–right symmetry breaking scale. If this scale happens to lie in the TeV range, several new particles potentially much lighter than the SUR(2) charged gauge bosons will be accessible at the LHC.

Figure 1: The Pioneer orbits in the interior of the solar system. 
Figure 2: A JPL Orbital Data Program (ODP) plot of the early unmodeled accelerations of Pioneer 10 and Pioneer 11, from about 1981 to 1989 and 1977 to 1989, respectively.
LA-UR-07-7264 New Horizons and the Onset of the Pioneer Anomaly

January 2008


117 Reads

Analysis of the radio tracking data from the Pioneer 10/11 spacecraft at distances between about 20–70 AU from the Sun has indicated the presence of an unmodeled, small, constant, Doppler blue shift which can be interpreted as a constant acceleration of aP=(8.74±1.33)×10−8 cm/s2 directed approximately towards the Sun. In addition, there is early (roughly modeled) data from as close in as 5 AU which indicates there may have been an onset of the anomaly near Saturn. We observe that the data now arriving from the New Horizons mission to Pluto and the Kuiper Belt could allow a relatively easy, direct experimental test of whether this onset is associated with distance from the Sun (being, for example, an effect of drag on dark matter). We strongly urge that this test be done.

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