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Measurement of the Rate of {nu}{sub e} + d {yields} p + p + e{sup -} Interactions Produced by B
Abstract
Solar neutrinos from {sup 8}B decay have been detected at the Sudbury Neutrino Observatory via the charged current (CC) reaction on deuterium and the elastic scattering (ES) of electrons. The flux of {nu}{sub e}'s is measured by the CC reaction rate to be {phi}{sup CC}({nu}{sub e}) =1.75{+-}0.07(stat){sup +0.12}{sub -0.11}(syst){+-}0.05(theor ) x 10{sup 6} cm{sup -2}s{sup -1}. Comparison of {phi}{sup CC}({nu}{sub e}) to the Super-Kamiokande Collaboration's precision value of the flux inferred from the ES reaction yields a 3.3{sigma} difference, assuming the systematic uncertainties are normally distributed, providing evidence of an active non-{nu}{sub e} component in the solar flux. The total flux of active {sup 8}B neutrinos is determined to be 5.44{+-}0.99 x 10{sup 6} cm {sup -2} s{sup -1}.
... Fascinatingly, the quantitative correspondence desired did not obtain when the first solar neutrino detection experiments where conducted (Davis et al., 1968). Rather, it is only after the hypothesis of neutrino oscillations that solar neutrino experiments sensitive to the different neutrino flavours could be devised (Ahmad et al., 2001). With these solar neutrino experiments, along with subsequent terrestrial neutrino experiments, the predicted solar neutrino flux could be corrected and the correspondence between observation and prediction obtained (Liccardo et al., 2018). ...
To demarcate the limits of experimental knowledge, we probe the limits of what might be called an experiment. By appeal to examples of scientific practice from astrophysics and analogue gravity, we demonstrate that the reliability of knowledge regarding certain phenomena gained from an experiment is not circumscribed by the manipulability or accessibility of the target phenomena. Rather, the limits of experimental knowledge are set by the extent to which strategies for what we call ‘inductive triangulation’ are available: that is, the validation of the mode of inductive reasoning involved in the source-target inference via appeal to one or more distinct and independent modes of inductive reasoning. When such strategies are able to partially mitigate reasonable doubt, we can take a theory regarding the phenomena to be well supported by experiment. When such strategies are able to fully mitigate reasonable doubt, we can take a theory regarding the phenomena to be established by experiment. There are good reasons to expect the next generation of analogue experiments to provide genuine knowledge of unmanipulable and inaccessible phenomena such that the relevant theories can be understood as well supported.
This article is part of a discussion meeting issue ‘The next generation of analogue gravity experiments’.
... Fascinatingly, the quantitative correspondence desired did not obtain when the first solar neutrino detection experiments where conducted (Davis et al., 1968). Rather, it is only after the hypothesis of neutrino oscillations that solar neutrino experiments sensitive to the different neutrino flavours could be devised (Ahmad et al., 2001). With these solar neutrino experiments, along with subsequent terrestrial neutrino experiments, the predicted solar neutrino flux could be corrected and the correspondence between observation and prediction obtained (Liccardo et al., 2018). ...
To demarcate the limits of experimental knowledge we probe the limits of what might be called an experiment. By appeal to examples of scientific practice from astrophysics and analogue gravity, we demonstrate that the reliability of knowledge regarding certain phenomena gained from an experiment is not circumscribed by the manipulability or accessibility of the target phenomena. Rather, the limits of experimental knowledge are set by the extent to which strategies for what we call `inductive triangulation' are available: that is, the validation of the mode of inductive reasoning involved in the source-target inference via appeal to one or more distinct and independent modes of inductive reasoning. When such strategies are able to partially mitigate reasonable doubt, we can take a theory regarding the phenomena to be well supported by experiment. When such strategies are able to fully mitigate reasonable doubt, we can take a theory regarding the phenomena to be established by experiment. There are good reasons to expect the next generation of analogue experiments to provide genuine knowledge of unmanipulable and inaccessible phenomena such that the relevant theories can be understood as well supported.
... In that context it is noteworthy that experiments geared toward measuring extraterrestrial neutrinos have already provided numerous important contributions to neutrino physics [e.g. [34][35][36][37][38][39]. UHE neutrinos can be used as an important probe of beyond Standard Model physics, neutrino cross sections [e.g. ...
Trinity is a proposed air-shower imaging system optimized for the detection of earth-skimming ultrahigh energy tau neutrinos with energies between $10^7$ GeV and $10^{10}$ GeV. Trinity will pursue three major scientific objectives. 1) It will narrow in on possible source classes responsible for the astrophysical neutrino flux measured by IceCube. 2) It will help find the sources of ultrahigh-energy cosmic rays (UHECR) and understand the composition of UHECR. 3) It will test fundamental neutrino physics at the highest energies. Trinity uses the imaging technique, which is well established and successfully used by the very high-energy gamma-ray community (CTA, H.E.S.S., MAGIC, and VERITAS) and the UHECR community (Telescope Array, Pierre Auger)
... The new evidence for neutrino oscillations from the Super-Kamiokande [1] (SK) and SNO experiments [2] has rekindled interest in neutrino physics. A proposed upgrade to the existing Alternating Gradient Synchrotron at BNL to a 1 MW facility would make a long baseline neutrino facility feasible. ...
This paper examines the feasibility of a long baseline neutrino beam facility based on a proposed upgrade to the AGS accelerator at Brookhaven National Laboratory. It assumes that the AGS is upgraded initially to a 1 MW proton driver and eventually to a 4 MW proton machine. This upgrade would provide a strong incentive for a long baseline low energy neutrino beam to study neutrino oscillations. In this paper we look at a possible long baseline experiment with a detector at Cornell, which is 350 km away from BNL.
The following thesis presents the result of a Beyond the Standard Model search for heavy resonances (V'/A) decaying into a Standard Model W or Z boson, and a Higgs (h) boson with a final state signature llbb̄, lνbb̄, or ννbb̄, where l= e/μ , in proton-proton collisions at a center of mass energy of √s = 13 TeV. The data is collected using the ATLAS detector at the Large Hadron Collider, during the data periods of 2015+2016, amounting to 36.1 fb^{-1}. The search is conducted using the (transverse) invariant mass spectrum of the reconstructed Standard Model W/Z boson and Higgs boson system, W/Z + h, to search for excesses using the CL_{s} binned profile likelihood test statistic. No excess is observed, therefore the results are interpreted in terms of constraints on σ_{V/A} × BR(h→bb̄), for heavy vector bosons predicted by Heavy Vector Triplet models (HVT ), W'/Z', or the CP-odd scalar boson A predicted by Two-Higgs Doublet Models (2HDM ). The upper limits on the production cross-sections are then used to assign constraints to the model parameter space. For the HVT interpretation, limits on two benchmark models corresponding to fermiophobic and fermiophilic extensions, labelled A and B, of the heavy resonances are set: m_{V'} = 2800(2930) GeV. For 2HDMs, limits on the production cross-section for mediator masses ranging from 220-2000 GeV are set: 5.5 × 10^{−3} pb → 2.4 × 10^{−1} pb for gg→A production, and 3.4 × 10^{−3} → 7.3 × 10^{−1} pb for bbA associated production.
Kamioka Underground Observatoris consist of three different organizations. Super-Kamikande is operated by the Kamioka Observatory, Institute for Cosmic Ray Research (the University of Tokyo) and KamLAND is operated by Research Center for Neutrino Science (Tohoku University). Those experiments in the Kamioka Underground Observatories have discovered neutrino oscillations and also made tremendous contributions on the oscillation studies after the discovery. The discovery of the neutrino oscillations was initially made by using the astrophysical neutrinos, but the experiments using man-made neutrinos from accelerators and nuclear reactors are also carried out. Underground we also have many devices necessary to achieve low-background environments. The Kamioka Satellite (Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo) provides indispensable devices for low-background experiments. They are commonly used. We also supply Rn-free air and pure water. The number of experiments underground have been increasing recently, including some R&D projects. Nowadays other fields of science like geo-physics are also pursued in the underground observatories. We have a future plan to scale up the Super-Kamiokande further, to be called Hyper-Kamiokande, and there will be a variety of possibilities using the KamLAND detector as a low-background environment. The full scale XMASS will also be an interesting future project.
The Kamiokande experiment was originally conceived and designed for the detection of
proton decay signals. In the early stage of the experiment, it was decided to upgrade the
detector so that astrophysical neutrinos including solar neutrinos in the 10 MeV energy
range can be detected. When the upgrade of the detector was almost completed, a neutrino
burst from Supernova SN1987A was detected. 2 years later, solar neutrinos were also
observed with the energy, the directional and the arrival time information. This article
describes the story of the Kamiokande experiment, and the subsequent development of the
neutrino physics, including the neutrino oscillation, and astrophysics with Kamiokande and
its successors; Super-Kamiokande and KamLAND.
A synopsis of lectures is presented which were delivered by the author in 2010 at the Baikal summer school on physics of elementary particles and astrophysics. The lectures are primarily intended for students, postgraduates, and young researchers as an introductory course on neutrino physics.
High-sensitivity searches for transitions of muon neutrinos to electron neutrinos are the main task of the T2K (Tokai-to-Kamioka) second-generation long-baseline accelerator neutrino experiment. The present article is devoted to describing basic principles of T2K, surveying experimental apparatuses that it includes, and considering in detail the muon-range detector (SMRD) designed and manufactured by a group of physicists from the Institute of Nuclear Research (Russian Academy of Sciences, Moscow). The results of the first measurements with a neutrino beam are presented, and plans for the near future are discussed.
Neutrinos are elementary particles in the Standard Model. Neutrino oscillation is a quantum mechanical phenomenon beyond the Standard Model. Neutrino oscillation can be described by two independent mass-squared differences Δm
212, Δm
312 (or Δm
322) and a 3 × 3 unitary matrix, containing three mixing angles θ
12, θ
23, θ
13, and one charge-parity (CP) phase. θ
12 is about 34° and determined by solar neutrino experiments and the reactor neutrino experiment KamLAND. θ
23 is about 45° and determined by atmospheric neutrino experiments and accelerator neutrino experiments. θ
13 can be measured by either accelerator or reactor neutrino experiments. On Mar. 8, 2012, the Daya Bay Reactor Neutrino Experiment reported the first observation of non-zero θ
13 with 5.2 standard deviations. In June, with 2.5× previous data, Daya Bay improved the measurement of sin22θ
13 = 0.089 ± 0.010(stat) ± 0.005(syst).
There is good agreement between the neutrino mass square difference determined from the solar neutrino and anti-neutrino mass square difference from the KamLAND reactor antineutrino. We consider as special case of matter density profile, which are relevant for neutrino oscillation physics. In particular, we compute to constrain a specific from of CPT violation in matter by upper bound,
$|\varDelta_{21}^{m}-\overline{\varDelta_{21}^{m}}| \ll 1.098\times10^{-4}~\mathrm{eV}^{2}$
and
$|\sin2\theta_{12}^{m}-\sin2\bar{\theta}_{12}^{m}|<0.0057$
. In this paper, we discuss CPT violation on neutrino oscillation in matter. The dispersion relation for the CPT violation in neutrino oscillation in matter are discussed.
The muon as a laboratory for studying charged lepton-flavour violation (cLFV) has proven to be one of the most sensitive areas to probe for “New Physics”, due to the muon’s copious production rate and relatively long lifetime. The search at the intensity frontier with precision-type experiments is complementary to the search for new particles at the high-energy frontier of TeV colliders. Of the three “golden” muon channels: μ → eγ, μ → 3e and μ → e
conversion, an overview of the status of the coincidence experiments MEG, together with the latest results, which constitute the most stringent limit to date on this decay and the recently initiated Mu3e experiment, will be given.
The T2K experiment searches for the appearance of electron neutrinos in a muon neutrino beam. The rate of this process is sensitive to the neutrino mixing parameter θ
13. Recent measurements that
$\theta_{13} \ne 0$
imply that ν
μ
→ ν
e
oscillations should be observable. Using all data through May 15, 2012 the T2K experiment has detected 10 candidate ν
e
events, with an expected background for θ
13 = 0 of 2.73±0.37 events. This 3.2σ excess of ν
e
events is the strongest indication to date for appearance of electron neutrinos in a neutrino oscillation experiment, and for normal mass hierarchy and δ
CP
= 0 yields
$0.059 < \sin^2 2\theta_{13} < 0.164$
at the 68 % C.L.
We study the rare decays of charged π mesons, π
+ → e
+e
+μ
−
$ \overline v $
μ
and π
+ → e
+μ
−e
+ν
e
induced by a sterile neutrino N with a mass in the range m
μ
< m
N
< m
π
. The first process violates Lepton Number by two units and so occurs only if N is Majorana, while the second process conserves Lepton Number and occurs irrespective of the Majorana or Dirac character of N . We study a way to distinguish the Majorana vs. Dirac character of N in these processes using the muon spectrum. We also find that the branching ratios could be at the reach of high luminosity experiments like Project X at FNAL or any proposed neutrino (or muon) factories worldwide.
A brief description of the path-breaking evidence for the observation of neutrino oscillations at the Sudbury Neutrino Observatory
is presented and the experimental principles and theory thereof are briefly discussed.
Oki Island is located between Japan and Korea along the Tokai-To-Kamioka (T2K) baseline. The distance from J-PARC to Oki Island is about 653km, which is twice that of the T2K experiment (L = 295km). When the off-axis angle of the neutrino beam from J-PARC is 3.0◦ (2.0◦) at Super-Kamiokande (SK), the off-axis beam (OAB) with 1.4◦ (0.6◦) reaches at Oki Island. We examine physics case of placing a far detector in Oki Island during the T2K experimental period. We estimate the matter density profile along the Tokai-to-Oki baseline by using recent seismological measurements. For a detector of 100 kton fiducial volume and 2.5 × 1021 POT (protons on target) exposure for both ν
μ
and \( {{\overline{\nu}}_{\mu }} \) beams, we find that the mass hierarchy pattern can be distinguished at 3 σ level if sin2 2θ
RCT ≡ 4|U
e3|2(1 − |U
e3
|2) ≳ 0.09, by observing the electron-like CCQE (Charged-Current Quasi Elastic) events. The CP phase in the Maki-Nakagawa-Sakata lepton flavor mixing matrix, δ
MNS, can be constrained with ±20◦. As a reference, we repeat the same analysis by placing the same detector in Korea at L = 1000 km and OAB=0.5◦ (T2KK) and also by placing it at the SK site (T2K122). The Tokai-to-Kamioka-OKI (T2KO) sensitivity to the mass hierarchy is about 1/3 (in \( \varDelta \chi_{\min}^2 \)) of T2KK, while the sensitivity to the phase δ
MNS is similar between T2KO and T2KK. The T2K122 option has almost no sensitivity to the mass hierarchy, and cannot measure the CP phase except when δ
MNS ~ −90◦ (90◦) for the normal (inverted) hierarchy.
Motivated by large ν µ − ν τ flavor mixing, we consider µτ production at hadron colliders via dimension-6 effective operators, which can be attributed to new physics in the flavor sector at a higher scale Λ. Current bounds on many of these operators from low energy experiments are very weak or nonexistent, and they may lead to clean µ + τ − and µ − τ + signals at hadron colliders. At the Tevatron with 8 fb −1 , one can exceed current bounds for most operators, with most 2σ sensitivities being in the 6 − 24 TeV range. We find that at the LHC with 1 fb −1 (100 fb −1) integrated luminosity, one can reach a 2σ sensitivity for Λ ∼ 3−10 TeV (Λ ∼ 6 − 21 TeV), depending on the Lorentz structure of the operator. For some operators, an improvement of several orders of magnitude in sensitivity can be obtained with only a few tens of pb −1 at the LHC.
Neutrino masses and mixings, which are key issues of neutrino physics, are studied by investigating low energy neutrinos (λ’s)
in nuclei as micro-laboratories. Nuclear spin isospin responses for λ’s are crucial for λ studies in nuclei. Nuclear charge-exchange
spinflip reactions are shown to be used for investigating nuclear spin isospin responses. Brief discussions are given on recent
studies of nuclear spin isospin responses for low energy λ’s such as solar and supernova λ’s, and for λ’s associated with
double beta decays (ββ). 100Mo is found to have large spin isospin responses for these low energy λ’s. Thus spectroscopic studies of ββ decays with a
sensitivity of (m
λ)≈0.03 eV and realtime studies of low energy solar λ’s are possible by MOON (Mo Observatory of Neutrinos) with multiton 100Mo.
We discuss effects of new physics (NP) in neutrino oscillation experiments. Such effects can modify a production neutrino
flux, a detection cross-section and a matter transition. As a result, the NP effects change neutrino oscillations both in
vacuum and in matter. A relation between the small effects of NP and the oscillation parameters is discussed. It is shown
for which parameters the NP effects are suppressed and when they are potentially large. Oscillations of non-unitary mixed
neutrinos are presented in more details.
We analyze here how solar neutrino experiments could detect time fluctuations of the solar neutrino flux due to magnetohydrodynamics
(MHD) perturbations of the solar plasma. We state that if such time fluctuations are detected, this would provide a unique
signature of the Resonant Spin-Flavor Precession (RSFP) mechanism as a solution to the Solar Neutrino Problem.
In 1970 Fred Hoyle encouraged a study of solar neutrino production which led to along-term investigation of the influence
of what have become known as `non-standard' processes (i.e. processes that are not accounted for in the relatively naively
constructed so-called `standard' theoretical solar models). The outcome is a very much sounder understanding of the structure
and dynamics of the Sun, which has yielded a knowledge of conditions in the energy-generating core so precise that one can
set quite tight reliable constraints on neutrino-producing nuclear reactions, and thereby provide an important contribution
to the study of neutrino transitions.
The influence of magnetized plasma on neutrino dispersion has been studied. The contribution to the neutrino magnetic moment
due to the presence of a magnetized plasma is calculated. It is shown that, in contrast to earlier published data, the plasma-induced
magnetic moment of a neutrino is, like that in a vacuum, suppressed by its mass.
The interior of the Sun is not directly observable to us. Nevertheless, it is possible to infer the physical conditions prevailing
in the solar interior with the help of theoretical models coupled with observational input provided by measured frequencies
of solar oscillations. The frequencies of these solar oscillations depend on the internal structure and dynamics of the Sun
and from the knowledge of these frequencies it is possible to infer the internal structure as well as the large scale flows
inside the Sun, in the same way as the observations of seismic waves on the surface of Earth help us in the study of its interior.
With the accumulation of seismic data over the last six years it has also become possible to study temporal variations in
the solar interior. Some of these seismic inferences would be described.
We study the predictions for sfermion masses and Lepton Flavour Violation (LFV) for the WMAP preferred parameter space in
b − τ Yukawa-unified models with massive neutrinos. A soft term structure as predicted by an Abelian flavour symmetry combined
with SU(5) RGEs for scales above M
GUT, results to an efficient suppression of the off-diagonal terms in the scalar soft matrices, particularly for m
0 < 100GeV. Using the WMAP bounds, this implies 35 ≤ tan β ≤ 45, 350GeV ≤ m
1/2 ≤ 1TeV, with the higher tan β values being favored. Within this framework, SU(5) unification becomes compatible with the
current experimental bounds, in contrast to the conventional case where the soft terms are postulated at the GUT scale.
KeywordsSupersymmetry Phenomenology
This is a summary of the projects undertaken by the working group I on high energy and collider physics.
We present a systematic study of 400 combinations of the charged lepton and neutrino mass matrices with six vanishing entries or texture zeros. Only 24 of them, which can be classified into a few distinct categories, are found to be compatible with current neutrino oscillation data at the
3s3\sigma
level. A peculiar feature of the lepton mass matrices in each category is that they have the same phenomenological consequences. Taking account of a simple seesaw scenario for six parallel patterns of the charged lepton and Dirac neutrino mass matrices with six zeros, we show that it is possible to fit the experimental data at or below the
2s2\sigma
level. In particular, the maximal atmospheric neutrino mixing can be reconciled with a strong neutrino mass hierarchy in the seesaw case. Numerical predictions are also obtained for the neutrino mass spectrum, flavor mixing angles, CP-violating phases and effective masses of the tritium beta decay and the neutrinoless double beta decay.
We investigate the prospects for detection of lepton flavour violation in
sparticle production and decays at a Linear Collider (LC), in models guided by
neutrino oscillation data. We consider both slepton pair production and
sleptons arising from the cascade decays of non-leptonic sparticles. We study
the expected signals when lepton-flavour-violating (LFV) interactions are
induced by renormalization effects in the Constrained Minimal Supersymmetric
extension of the Standard Model (CMSSM), focusing on the subset of the
supersymmetric parameter space that also leads to cosmologically interesting
values of the relic neutralino LSP density. Emphasis is given to the
complementarity between the LC, which is sensitive to mixing in both the left
and right slepton sectors, and the LHC, which is sensitive primarily to mixing
in the right sector. We also emphasize the complementarity between searches for
rare LFV processes at the LC and in low-energy experiments.
We investigate the possibility of detecting single sqaurk production at the
proposed LHeC collider, in the framework of R-parity violating supersymmetry.
Taking advantage of the enhancement of the direct resonance production of
squark and the distinctive kinematics distributions of $\tilde{q}\rightarrow l
q$ two body decay final states, the LHeC provides excellent opportunities of
probing R-violating $\hat{L}\hat{Q}\hat{D}$ interactions at unprecedented level
compared to all the knowledge derived from indirect low energy nucleon
measurements. If no apparent deviation from SM predictions on high invariant
mass of muon and b-quark final states at the LHeC with 1$fb^{-1}$ data, the
sensitivities on $\hat{L}\hat{Q}\hat{D}$ coupling constant $\lambda^{'}_{131}
\times \lambda^{'}_{233}$ can be improved by nearly four orders, at energy
scale about 100 GeV.
We update our study of neutrino mass hierarchy determination using a high
statistics reactor electron anti-neutrino experiment in the light of the recent
evidences of a relatively large non-zero value of \theta_{13} from the Daya Bay
and RENO experiments. We find that there are noticeable modifications in the
results, which allow a relaxation in the detector's characteristics, such as
the energy resolution and exposure, required to obtain a significant
sensitivity to, or to determine, the neutrino mass hierarchy in such a reactor
experiment.
This article extends the work of Bernabeu and Espinoza by examining the CP-violation reach of a 150Dy electron capture beam through the variation of the two Lorentz boosts, the number of useful electron capture decays, the relative run time of each boost and the number of atmospheric backgrounds. The neutrinos are assumed to be sourced at CERN with an upgraded SPS and are directed towards a 440 kton Water Cerenkov detector located at the Canfranc laboratory. Two large ‘CP-coverage’ choices for the boost pairings are found; a δ-symmetrical coverage for (γ
1, γ
2) = (280, 160) and an δ-asymmetric coverage for (γ
1, γ
2) = (440,150). With a nominal useful decay rate of N
ions = 1018 ions per year, the δ-symmetric setup can rule out CP-conservation down to sin2 2θ
13 = 3∙10−4. To reach sin2 2θ
13 =1∙10−3 for both δ < 0 and δ > 0 requires a useful decay rate of N
ions = 6∙1017 ions per year.
The much needed nuclear input to the Standard Solar Model, S
17(0), has now been measured with high precision (±5% or better) by different groups and good agreement is found, even when very different methods are employed. We review the decade long research program to measure the cross section of the 7Be(p,γ)8B reaction using the Coulomb dissociation method, including the pioneering RIKEN1 experiment carried out during March 1992, followed by RIKEN2, GSI1, GSI2 and an MSU experiment. Our RIKEN and GSI data allow us to rule out the much tooted large E2 contribution to the Coulomb dissociation of 8B. Specifically recent results of the MSU experiment are not confirmed. The GSI1 and GSI2 high precision measurements are in good (to perfect) agreement with the newly published high precision measurements of direct capture with 7Be targets. From these GSI-Seattle-Weizmann high precision data we conclude that the astrophysical cross section factor, S
17(0), is most likely in the range of 20–22 eV-b. We point out to an additional large uncertainty (−10% +3%) that still exists due to uncertainty in the measured slope of the S-factor and the theoretical extrapolation procedure which may still lower S
17(0) down to approximately 18.5 eV-b. For quoting S
17(0) with an uncertainty of ±5% or better, yet another measurement needs to be performed at very low energies, as recently discussed by the UConn-Weizmann-LLN collaboration for the CERN/ISOLDE facility.
The aim of the μCap experiment is a 1% measurement of the singlet capture rate ΛS
for the basic electro-weak reaction μ + p → n + νμ. This observable is sensitive to the weak form-factors of the nucleon, in particular to the induced pseudoscalar coupling constant g
P
. It will provide a rigorous test of theoretical predictions based on the Standard Model and effective theories of QCD. The present method is based on high precision lifetime measurements of μ− in hydrogen gas and the comparison with the free μ+ lifetime. The μ− experiment will be performed in ultra-clean, deuterium-depleted H2 gas at 10 bar. Low density compared to liquid H2 is chosen to avoid uncertainties due to ppμ formation. A time projection chamber acts as a pure hydrogen active target. It defines the muon stop position in 3D and detects rare background reactions. Decay electrons are tracked in cylindrical wire-chambers and a scintillator array covering 75% of 4π.
We report about an analytic study involving the {\em intermediate} wave
packet formalism for quantifying the physically relevant information which
appear in the neutrino two-flavor conversion formula and help us to obtain more
precise limits and ranges for neutrino flavor oscillation. By following the
sequence of analytic approximations where we assume a strictly peaked momentum
distribution and consider the second-order corrections in a power series
expansion of the energy, we point out a {\em residual} time-dependent phase
which, coupled with the {\em spreading/slippage} effects, can subtly modify the
neutrino oscillation parameters and limits. Such second-order effects are
usually ignored in the relativistic wave packet treatment, but they present an
evident dependence on the propagation regime so that some small modifications
to the oscillation pattern, even in the ultra-relativistic limit, can be
quantified. These modifications are implemented in the confront with the
neutrino oscillation parameter range (mass-squared difference $\Delta m^{\2}$
and the mixing-angle $\theta$) where we assume the same wave packet parameters
previously noticed in the literature in a kind of {\em toy model} for some
reactor experiments. Generically speaking, our analysis parallels the recent
experimental purposes which concern with higher precision parameter
measurements. To summarize, we show that the effectiveness of a more accurate
determination of $\Delta m^{\2}$ and $\theta$ depends on the wave packet width
$a$ and on the averaged propagating energy flux $\bar{E}$ which still
correspond to open variables for some classes of experiments. \
The Beta Beam CERN design is based on the present LHC injection complex and
its physics reach is mainly limited by the maximum rigidity of the SPS. In
fact, some of the scenarios for the machine upgrades of the LHC, particularly
the construction of a fast cycling 1 TeV injector (``Super-SPS''), are very
synergic with the construction of a higher $\gamma$ Beta Beam. At the energies
that can be reached by this machine, we demonstrate that dense calorimeters can
already be used for the detection of $\nu$ at the far location. Even at
moderate masses (40 kton) as the ones imposed by the use of existing
underground halls at Gran Sasso, the CP reach is very large for any value of
$\theta_{13}$ that would provide evidence of $\nu_e$ appearance at T2K or
NO$\nu$A ($\theta_{13}\geq 3^\circ$). Exploitation of matter effects at the
CERN to Gran Sasso distance provides sensitivity to the neutrino mass hierarchy
in significant areas of the $\theta_{13}-\delta$ plane.
We derive a new set of sum rules between the neutrino masses and mixing parameters in vacuum and their effective counterparts in matter. By using the novel sum rules, a geometric description of lepton flavor mixing and CP violation in matter is presented in the language of leptonic unitarity triangles. The exact analytical relations for both sides and inner angles of unitarity triangles are established. The typical shape evolution of unitarity triangles with the terrestrial matter density is illustrated for a realistic long-baseline neutrino oscillation experiment.
We show that it is possible to enforce texture zeros in arbitrary entries of the fermion mass matrices by means of Abelian symmetries; in this way, many popular mass-matrix textures find a symmetry justification. We propose two alternative methods which allow to place zeros in any number of elements of the mass matrices that one wants. They are applicable simultaneously in the quark and lepton sectors. They are also applicable in Grand Unified Theories. The number of scalar fields required by our methods may be large; still, in many interesting cases this number can be reduced considerably. The larger the desired number of texture zeros is, the simpler are the models which reproduce the texture. Comment: 13 pages, no figures, plain LaTeX; misprints corrected, a few sentences changed, one reference added, final version for Eur. Phys. J. C
This article summarises the status of the solar neutrino oscillation phenomenology at the end of 2002 in the light of the SNO and KamLAND results. We first present the allowed areas obtained from global solar analysis and demonstrate the preference of the solar data towards the large-mixing-angle (LMA) MSW solution. A clear confirmation in favour of the LMA solution comes from the KamLAND reactor neutrino data. The KamLAND spectral data in conjunction with the global solar data further narrows down the allowed LMA region and splits it into two allowed zones a low Δm
2 region (low-LMA) and high Δm
2 region (high-LMA). We demonstrate through a projected analysis that with an exposure of 3 kton-year (kTy) KamLAND can remove this ambiguity.
A short review of the status of neutrino mixing and neutrino oscillations is given. The basics of neutrino mixing and oscillations is discussed. The latest evidences of neutrino oscillations obtained in the Super-Kamiokande and the SNO solar neutrino experiments and in the Super-Kamiokande atmospheric neutrino experiment are considered. The results of solar and atmospheric neutrino experiments are discussed from the point of view of the three-neutrino mixing. Comment: 20 pages, Proceedings of the Advanced Study Institute "Symmetries and Spin", Praha-Spin-2001, Czech Republic, July 15-28, 2001
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