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ABSTRACT: We propose an interpretation of the two neutrino initiated cascade events
with PeV energies observed by IceCube: Ultra-high energy cosmic ray protons (or
Fe nuclei) scatter on CMB photons through the Delta-resonance (the
Berezinsky-Zatsepin process) yielding charged pions and neutrons. The neutron
decays give electron-antineutrinos which undergo neutrino oscillations to
populate all antineutrino flavors, but the electron-antineutrino flux remains
dominant. At 6.3 PeV electron-antineutrino energy their annihilation on
electrons in the IceCube detector is enhanced by the Glashow resonance (the
W-boson) whose decays can give the PeV showers observed in the IceCube
detector. The two observed showers with ~1 PeV energies would need to be from W
leptonic decays to electrons and taus. An order of magnitude higher event rate
of showers at 6.3 PeV is predicted from W to hadron decays. This interpretation
can be tested in the near term. It has significant physics implications on the
origin of the highest energy cosmic rays, since neutrino events and cosmic ray
events likely share a common origin.
07/2012;
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[show abstract]
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ABSTRACT: Stoponium, a bound state of top squark and its antiparticle in a
supersymmetric model, may be found in the ongoing Higgs searches at the LHC.
Its WW and ZZ detection ratios relative to the Standard Model Higgs boson can
be more than unity from WW* threshold to the two Higgs threshold. The gamma
gamma channel is equally promising. Some regions of the stoponium mass below
150 GeV are already being probed by the ATLAS and CMS experiments.
10/2011;
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[show abstract]
[hide abstract]
ABSTRACT: Data from the LSND and MiniBooNE experiments, and revised expectations of the
antineutrino flux from nuclear reactors suggest the existence of eV-mass
sterile neutrinos. 3+2 and 1+3+1 scenarios accommodate all relevant
short-baseline neutrino data except for the low-energy MiniBooNE anomaly. We
analyze the angular distribution of upward going atmospheric neutrino events in
the IceCube-40 dataset for evidence of sterile neutrinos within these
scenarios. Depending on how systematic uncertainties are handled, we find
strong evidence for, or weak evidence against sterile neutrinos. We show that
future IceCube data will definitively settle the issue.
09/2011;
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[show abstract]
[hide abstract]
ABSTRACT: With the augmentation of IceCube by DeepCore, the prospect for detecting dark
matter annihilation in the Sun is much improved. To complement this
experimental development, we provide a thorough template analysis of the
particle physics issues that are necessary to precisely interpret the data. Our
study is about nitty-gritty and is intended as a framework for detailed work on
a variety of dark matter candidates. To accurately predict the source neutrino
spectrum, we account for spin correlations of the final state particles and the
helicity-dependence of their decays, and absorption effects at production. We
fully treat the propagation of neutrinos through the Sun, including neutrino
oscillations, energy losses and tau regeneration. We simulate the survival
probability of muons produced in the Earth by using the Muon Monte Carlo
program, reproduce the published IceCube effective area, and update the
parameters in the differential equation that approximates muon energy losses.
To evaluate the zenith-angle dependent atmospheric background event rate, we
track the Sun and determine the time it spends at each zenith angle.
Throughout, we employ neutralino dark matter as our example.
01/2011;
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Phys. Rev. D. 11/2009; 80(9).
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A Bandyopadhyay,
S Choubey,
R Gandhi,
S Goswami,
B L Roberts,
J Bouchez,
I Antoniadis,
J Ellis,
G F Giudice,
T Schwetz, [......],
J W F Valle,
P F Harrison,
C Lunardini,
J K Nelson, V Barger,
L Everett,
P Huber,
W Winter,
W Fetscher,
A van der Schaaf
[show abstract]
[hide abstract]
ABSTRACT: The conclusions of the Physics Working Group of the International Scoping Study of a future Neutrino Factory and super-beam facility (the ISS) are presented. The ISS was carried out by the international community between NuFact05, (the 7th International Workshop on Neutrino Factories and Super-beams, Laboratori Nazionali di Frascati, Rome, 21–26 June 2005) and NuFact06 (Ivine, CA, 24–30 August 2006). The physics case for an extensive experimental programme to understand the properties of the neutrino is presented and the role of high-precision measurements of neutrino oscillations within this programme is discussed in detail. The performance of second-generation super-beam experiments, beta-beam facilities and the Neutrino Factory are evaluated and a quantitative comparison of the discovery potential of the three classes of facility is presented. High-precision studies of the properties of the muon are complementary to the study of neutrino oscillations. The Neutrino Factory has the potential to provide extremely intense muon beams and the physics potential of such beams is discussed in the final section of the report.
Reports on Progress in Physics 09/2009; 72(10):106201. · 14.72 Impact Factor
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ABSTRACT: We describe a characteristic signature of dark matter (DM) annihilation or decay into gamma-rays. We show that if the total angular momentum of the initial DM particle(s) vanishes, and helicity suppression operates to prevent annihilation/decay into light fermion pairs, then the amplitude for the dominant 3-body final state f^+f^-\gamma has a unique form dictated by gauge invariance. This amplitude and the corresponding energy spectra hold for annihilation of DM Majorana fermions or self-conjugate scalars, and for decay of DM scalars, thus encompassing a variety of possibilities. Within this scenario, we analyze Fermi LAT, PAMELA and HESS data, and predict a hint in future Fermi gamma-ray data that portends a striking signal at atmospheric Cherenkov telescopes (ACTs). Comment: 9 pages, 4 figures. Version to appear in PRD
06/2009;
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[show abstract]
[hide abstract]
ABSTRACT: We analyze new diffuse gamma-ray data from the Fermi Gamma-ray Space Telescope, which do not confirm an excess in the EGRET data at galactic mid-latitudes, in combination with measurements of electron and positron fluxes from PAMELA, Fermi and HESS within the context of three possible sources: dark matter (DM) annihilation or decay into charged leptons, and a continuum distribution of pulsars. We allow for variations in the backgrounds, consider several DM halo profiles, and account for systematic uncertainties in data where possible. We find that all three scenarios represent the data well. The pulsar description holds for a wide range of injection energy spectra. We compare with ATIC data and the WMAP haze where appropriate, but do not fit these data since the former are discrepant with Fermi data and the latter are subject to large systematic uncertainties. We show that for cusped halo profiles, Fermi could observe a spectacular gamma-ray signal of DM annihilation from the galactic center while seeing no excess at mid-latitudes.
Physics Letters B. 04/2009;
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S. Raby,
T. Walker,
K. S. Babu,
H Baer,
A. B. Balantekin, V. Barger,
Z. Berezhiani,
A. de Gouvea,
R. Dermisek,
A. Dolgov, [......],
R. N. Mohapatra,
P. Nath,
Y. Nomura,
K. A. Olive,
J. Pati,
S. Profumo,
R. Shrock,
Z. Tavartkiladze,
K. Whisnant,
L. Wolfenstein
[show abstract]
[hide abstract]
ABSTRACT: The NSF has chosen the site for the Deep Underground Science and Engineering Laboratory (DUSEL) to be in Lead, South Dakota. In fact, the state of South Dakota has already stepped up to the plate and contributed its own funding for the proposed lab, see http://www.sanfordlaboratoryathomestake.org/index.html. The final decision by NSF for funding the Initial Suite of Experiments for DUSEL will be made early in 2009. At that time the NSF Science Board must make a decision. Of order 200 experimentalists have already expressed an interest in performing experiments at DUSEL. In order to assess the interest of the theoretical community, the Center for Cosmology and Astro-Particle Physics (CCAPP) at The Ohio State University (OSU) organized a 3-day DUSEL Theory Workshop in Columbus, Ohio from April 4 - 6, 2008. The workshop focused on the scientific case for six proposed experiments for DUSEL: long baseline neutrino oscillations, proton decay, dark matter, astrophysical neutrinos, neutrinoless double beta decay and N-Nbar oscillations. The outcome of this workshop is the DUSEL Theory White paper addressing the scientific case at a level which may be useful in the decision making process for policy makers at the NSF and in the U.S. Congress. In order to assess the physics interest in the DUSEL project we have posted the DUSEL Theory White paper on the following CCAPP link http://ccapp.osu.edu/whitepaper.html . Please read the white paper and, if you are interested, use the link to show your support by co-signing the white paper.
11/2008;
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ABSTRACT: Assuming that the positron excess in PAMELA satellite data is a consequence of annihilations of cold dark matter, we consider from a model-independent perspective if the data show a preference for the spin of dark matter, and find that they do not. We then perform a general analysis of annihilations into two-body states to determine what weighted combination of channels best describes the data.
Physics Letters B. 09/2008;
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V. Barger,
M Bishai,
D. Bogert,
C Bromberg,
A. Curioni,
M. Dierckxsens,
M. Diwan,
F. Dufour,
D. Finley,
B. T. Fleming, [......],
N. Simos,
R. Van Berg,
B. Viren,
K. Whisnant,
R Wilson,
W. Winter,
C Yanagisawa,
F Yumiceva,
E. D. Zimmerman,
R. Zwaska
[show abstract]
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ABSTRACT: This report provides the results of an extensive and important study of the potential for a U.S. scientific program that will extend our knowledge of neutrino oscillations well beyond what can be anticipated from ongoing and planned experiments worldwide. The program examined here has the potential to provide the U.S. particle physics community with world leading experimental capability in this intensely interesting and active field of fundamental research. Furthermore, this capability could be unique compared to anywhere else in the world because of the available beam intensity and baseline distances. The present study was initially commissioned in April 2006 by top research officers of Brookhaven National Laboratory and Fermi National Accelerator Laboratory and, as the study evolved, it also provided responses to questions formulated and addressed to the study group by the Neutrino Scientific Advisory Committee (NuSAG) of the U.S. DOE and NSF. The participants in the study, its Charge and history, plus the study results and conclusions are provided in this report and its appendices. A summary of the conclusions is provided in the Executive Summary.
06/2007;
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ABSTRACT: We discuss the physics of superbeam upgrades, where we focus on T2KK, a NuMI beam line based experiment NOvA*, and a wide band beam (WBB) experiment independent of the NuMI beam line. For T2KK, we find that the Japan-Korea baseline helps resolve parameter degeneracies, but the improvement due to correlated systematics between the two detectors (using identical detectors) is only moderate. For an upgrade of NOvA with a liquid argon detector, we demonstrate that the Ash River site is preferred compared to alternatives, such as at the second oscillation maximum, and is the optimal site within the U.S. For a WBB experiment, we find that high proton energies and long decay tunnels are preferable. We compare water Cherenkov and liquid argon technologies, and find the break-even point in detector cost at about 4:1. In order to compare the physics potential of the different experimental configurations, we use the concept of exposure to normalize the performance. We find that experiments with WBBs are the best experimental concept. NOvA* could be competitive with sufficient luminosity. If $\sin^2 2\theta_{13}$ > 0.01, a WBB experiment can perform better than a neutrino factory.
04/2007;
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M. Diwan,
S. Kettell,
L. Littenberg,
W. Marciano,
Z. Parsa,
N. Samios,
S White,
R. Lanou,
W. Leland,
K. Lesko, [......],
K. Lande,
A. K. Mann,
R. Van Berg,
K T McDonald,
D. B. Cline,
P. Huber, V. Barger,
D. Marfatia,
T. Kirk,
R Potenza
[show abstract]
[hide abstract]
ABSTRACT: This report is intended to describe first, the principal physics reasons for an ambitious experimental program in neutrino physics and proton decay based on construction of a series of massive water Cherenkov detectors located deep underground (4850 ft) in the Homestake Mine of the South Dakota Science and Technology Authority (SDSTA); and second, the engineering design of the underground chambers to house the Cherenkov detector modules; and third, the conceptual design of the water Cherenkov detectors themselves for this purpose. Included in this document are preliminary costs and time-to-completion estimates which have been exposed to acknowledged experts in their respective areas. We have included some contingency factors. Nevertheless, we recognize that much more extensive documentation and contingency estimates will be needed for a full technical design report. In this proposal we show the event rates and physics sensitivity for beams from both FNAL (1300 km distant from Homestake) and BNL (2540 km distant from Homestake). The program we propose will benefit from a beam from FNAL because of the high intensities currently available from the Main Injector with modest upgrades. The possibility of tuning the primary proton energy over a large range from 30 to 120 GeV also adds considerable flexibility to the program from FNAL.
09/2006;
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S. Kraml,
E. Accomando,
A. G. Akeroyd,
E. Akhmetzyanova,
J Albert,
A. Alves,
N Amapane,
M Aoki,
G Azuelos,
S. Baffioni, [......],
F. von der Pahlen,
G. Weiglein,
J Williams,
K Williams,
A.F. \.Zarnecki,
D. Zeppenfeld,
D Zerwas,
P. M. Zerwas,
A. R. Zerwekh,
J. Ziethe
[show abstract]
[hide abstract]
ABSTRACT: There are many possibilities for new physics beyond the Standard Model that feature non-standard Higgs sectors. These may introduce new sources of CP violation, and there may be mixing between multiple Higgs bosons or other new scalar bosons. Alternatively, the Higgs may be a composite state, or there may even be no Higgs at all. These non-standard Higgs scenarios have important implications for collider physics as well as for cosmology, and understanding their phenomenology is essential for a full comprehension of electroweak symmetry breaking. This report discusses the most relevant theories which go beyond the Standard Model and its minimal, CP-conserving supersymmetric extension: two-Higgs-doublet models and minimal supersymmetric models with CP violation, supersymmetric models with an extra singlet, models with extra gauge groups or Higgs triplets, Little Higgs models, models in extra dimensions, and models with technicolour or other new strong dynamics. For each of these scenarios, this report presents an introduction to the phenomenology, followed by contributions on more detailed theoretical aspects and studies of possible experimental signatures at the LHC and other colliders.
09/2006;
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[show abstract]
[hide abstract]
ABSTRACT: We carry out a state-of-the-art assessment of long baseline neutrino oscillation experiments with wide band beams. We describe the feasibility of an experimental program using existing high energy accelerator facilities, a new intense wide band neutrino beam (0-6 GeV) and a proposed large detector in a deep underground laboratory. We find that a decade-long program with 1 MW operation in the neutrino mode and 2 MW operation in the antineutrino mode, a baseline as long as the distance between Fermilab and the Homestake mine (1300 km) or the Henderson mine (1500 km), and a water Cherenkov detector with fiducial mass of about 300 kT has optimum sensitivity to \theta_{13}, the mass hierarchy and to neutrino CP violation at the 3\sigma C.L. for \sin^22\theta_{13}>0.008. This program is capable of breaking the eight-fold degeneracy down to the octant degeneracy without additional external input.
08/2006;
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S. Kraml,
E. Accomando,
A. G. Akeroyd,
E. Akhmetzyanova,
J. Albert,
A. Alves,
N. Amapane,
M. Aoki,
G. Azuelos,
S. Baffioni, [......],
F. von der Pahlen,
G. Weiglein,
J. Williams,
K. Williams,
A. F. Zarnecki,
D. Zeppenfeld,
D. Zerwas,
P. M. Zerwas,
A. R. Zerwekh,
J. Ziethe
[show abstract]
[hide abstract]
ABSTRACT: There are many possibilities for new physics beyond the Standard Model
that feature non-standard Higgs sectors. These may introduce new sources
of CP violation, and there may be mixing between multiple Higgs bosons
or other new scalar bosons. Alternatively, the Higgs may be a composite
state, or there may even be no Higgs at all. These non-standard Higgs
scenarios have important implications for collider physics as well as
for cosmology, and understanding their phenomenology is essential for a
full comprehension of electroweak symmetry breaking. This report
discusses the most relevant theories which go beyond the Standard Model
and its minimal, CP-conserving supersymmetric extension:
two-Higgs-doublet models and minimal supersymmetric models with CP
violation, supersymmetric models with an extra singlet, models with
extra gauge groups or Higgs triplets, Little Higgs models, models in
extra dimensions, and models with technicolour or other new strong
dynamics. For each of these scenarios, this report presents an
introduction to the phenomenology, followed by contributions on more
detailed theoretical aspects and studies of possible experimental
signatures at the LHC and other colliders.
07/2006;
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J. A. Aguilar-Saavedra,
A. Ali,
B. C. Allanach,
R. Arnowitt,
H. A. Baer,
J. A. Bagger,
C. Balazs, V. Barger,
M. Barnett,
A. Bartl, [......],
G. Weiglein,
P. Wienemann,
Z.-Z. Xing,
Y. Yamada,
J. M. Yang,
D. Zerwas,
P. M. Zerwas,
R.-Y. Zhang,
X. Zhang,
S.-H. Zhu
[show abstract]
[hide abstract]
ABSTRACT: High-precision analyses of supersymmetry parameters aim at reconstructing the fundamental supersymmetric theory and its breaking
mechanism. A well defined theoretical framework is needed when higher-order corrections are included. We propose such a scheme,
Supersymmetry Parameter Analysis SPA, based on a consistent set of conventions and input parameters. A repository for computer
programs is provided which connect parameters in different schemes and relate the Lagrangian parameters to physical observables
at LHC and high energy e + e- linear collider experiments, i.e., masses, mixings, decay widths and production cross sections for supersymmetric particles.
In addition, programs for calculating high-precision low energy observables, the density of cold dark matter (CDM) in the
universe as well as the cross sections for CDM search experiments are included. The SPA scheme still requires extended efforts
on both the theoretical and experimental side before data can be evaluated in the future at the level of the desired precision.
We take here an initial step of testing the SPA scheme by applying the techniques involved to a specific supersymmetry reference
point.
European Physical Journal C 03/2006; 46(1):43-60. · 3.63 Impact Factor
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J. A. Aguilar-Saavedra,
A Ali,
B. C. Allanach,
R. Arnowitt,
H. A. Baer,
J. A. Bagger,
C. Balazs, V. Barger,
M Barnett,
A. Bartl, [......],
G. Weiglein,
P. Wienemann,
Z.-Z. Xing,
Y Yamada,
J. M. Yang,
D Zerwas,
P. M. Zerwas,
R.-Y. Zhang,
X Zhang,
S.-H. Zhu
[show abstract]
[hide abstract]
ABSTRACT: High-precision analyses of supersymmetry parameters aim at reconstructing the fundamental supersymmetric theory and its breaking mechanism. A well defined theoretical framework is needed when higher-order corrections are included. We propose such a scheme, Supersymmetry Parameter Analysis SPA, based on a consistent set of conventions and input parameters. A repository for computer programs is provided which connect parameters in different schemes and relate the Lagrangian parameters to physical observables at LHC and high energy e+e- linear collider experiments, i.e., masses, mixings, decay widths and production cross sections for supersymmetric particles. In addition, programs for calculating high-precision low energy observables, the density of cold dark matter (CDM) in the universe as well as the cross sections for CDM search experiments are included. The SPA scheme still requires extended efforts on both the theoretical and experimental side before data can be evaluated in the future at the level of the desired precision. We take here an initial step of testing the SPA scheme by applying the techniques involved to a specific supersymmetry reference point.
12/2005;
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[show abstract]
[hide abstract]
ABSTRACT: We study the proposal that mass-varying neutrinos could provide an explanation for the LSND signal for \bar\nu_mu to \bar\nu_e oscillations. We first point out that all positive oscillation signals occur in matter and that three active mass-varying neutrinos are insufficient to describe all existing neutrino data including LSND. We then examine the possibility that a model with four mass-varying neutrinos (three active and one sterile) can explain the LSND effect and remain consistent with all other neutrino data. We find that such models with a 3+1 mass structure in the neutrino sector may explain the LSND data and a null MiniBooNE result for 0.10 < \sin^2 2\theta_x < 0.30. Predictions of the model include a null result at Double-CHOOZ, but positive signals for underground reactor experiments and for \nu_\mu to \nu_e oscillations in long-baseline experiments. Comment: 22 pages, 3 figures, 1 table. Comment added about recent MINOS data
09/2005;
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C. Albright, V. Barger,
J. Beacom,
S. Brice,
J. J. Gomez-Cadenas,
M Goodman,
D Harris,
P. Huber,
A. Jansson,
M. Lindner,
O. Mena,
P. Rapidis,
K. Whisnant,
W. Winter,
The Neutrino Factory,
Muon Collider Collaboration
[show abstract]
[hide abstract]
ABSTRACT: The long-term prospects for fully exploring three-flavor mixing in the neutrino sector depend upon an ongoing and increased investment in the appropriate accelerator R&D. Two new concepts have been proposed that would revolutionize neutrino experiments, namely the Neutrino Factory and the Beta Beam facility. These new facilities would dramatically improve our ability to test the three-flavor mixing framework, measure \textsl{CP} violation in the lepton sector, and perhaps determine the neutrino mass hierarchy, and, if necessary, probe extremely small values of the mixing angle $\theta_{13}$. The stunning sensitivity that could be achieved with a Neutrino Factory is described, together with our present understanding of the corresponding sensitivity that might be achieved with a Beta Beam facility. In the Beta Beam case, additional study is required to better understand the optimum Beta Beam energy, and the achievable sensitivity. Neither a Neutrino Factory nor a Beta Beam facility could be built without significant R&D. An impressive Neutrino Factory R&D effort has been ongoing in the U.S. and elsewhere over the last few years and significant progress has been made towards optimizing the design, developing and testing the required accelerator components, and significantly reducing the cost. The recent progress is described here. Comment: 115 pages; 71 figures. The Neutrino Factory and Beta Beam Experiments and Development Working Group report to the Joint DNP/DPF/DAP/DPB Study on the Future of Neutrino Physics. A few typos corrected Several new references added in section 4
11/2004;
