共查询到20条相似文献,搜索用时 15 毫秒
1.
Precision experiments with muons are sensitive to Planck-scale CPT and Lorentz violation that is undetectable in other tests. Existing data on the muonium ground-state hyperfine structure and on the muon anomalous magnetic moment could be analyzed to provide dimensionless figures of merit for CPT and Lorentz violation at the levels of 4x10(-21) and 10(-23). 相似文献
2.
Exceptional sensitivity to space-time torsion can be achieved by searching for its couplings to fermions. Recent experimental searches for Lorentz violation are exploited to extract new constraints involving 19 of the 24 independent torsion components down to levels of order 10(-31) GeV. 相似文献
3.
Ralf Lehnert 《Hyperfine Interactions》2009,193(1-3):275-281
4.
Chiu Man Ho 《Physics letters. [Part B]》2011,702(5):398-401
We construct a model in which neutrinos and anti-neutrinos acquire the same mass but slightly different energy dispersion relations. Despite CPT violation, spin-statistics is preserved. We find that leptogenesis can be easily explained within this model, without upsetting the solar, atmospheric and reactor neutrino data. Leptogenesis occurs without lepton-number violation and the non-equilibrium condition. We consider only three active Dirac neutrinos, and no new particles or symmetries are introduced. 相似文献
5.
Aubert B Bona M Boutigny D Karyotakis Y Lees JP Poireau V Prudent X Tisserand V Zghiche A Garra Tico J Grauges E Lopez L Palano A Pappagallo M Eigen G Stugu B Sun L Abrams GS Battaglia M Brown DN Button-Shafer J Cahn RN Groysman Y Jacobsen RG Kadyk JA Kerth LT Kolomensky YG Kukartsev G Lopes Pegna D Lynch G Mir LM Orimoto TJ Osipenkov IL Ronan MT Tackmann K Tanabe T Wenzel WA Del Amo Sanchez P Hawkes CM Watson AT Koch H Schroeder T Walker D Asgeirsson DJ Cuhadar-Donszelmann T Fulsom BG Hearty C 《Physical review letters》2008,100(13):131802
We report results of a search for CPT and Lorentz violation in B(0)-B[over ](0) oscillations using inclusive dilepton events from 232 x 10(6) Upsilon(4S)-->BB[over ] decays recorded by the BABAR detector at the PEP-II B Factory at SLAC. We find 2.8sigma significance, compatible with no signal, for variations in the complex CPT violation parameter z at the Earth's sidereal frequency and extract values for the quantities Deltaa(micro) in the general Lorentz-violating standard-model extension. The spectral powers for variations in z over the frequency range 0.26 yr(-1) to 2.1 solar day(-1) are also compatible with no signal. 相似文献
6.
D. Colladay 《Physics of Atomic Nuclei》2000,63(6):1097-1102
One possible ramification of unified theories of nature such as string theory that may underlie the conventional standard model is the possible spontaneous breakdown of Lorentz and CPT symmetry. In this talk, the formalism for inclusion of such effects into a low-energy effective field theory is presented. An extension of the standard model that includes Lorentz-and CPT-breaking terms is developed. The restriction of the standard model extension to the QED sector is then discussed. 相似文献
7.
Geer S Marriner J Martens M Ray RE Streets J Wester W Hu M Snow GR Armstrong T Buchanan C Corbin B Lindgren M Muller T Gustafson R 《Physical review letters》2000,84(4):590-593
A search for antiproton decay has been made at the Fermilab Antiproton Accumulator. Limits are placed on fifteen antiproton decay modes. The results are used to place limits on the characteristic mass scale m(X) that could be associated with CPT violation accompanied by baryon number violation. 相似文献
8.
Greenberg OW 《Physical review letters》2002,89(23):231602
A interacting theory that violates CPT invariance necessarily violates Lorentz invariance. On the other hand, CPT invariance is not sufficient for out-of-cone Lorentz invariance. Theories that violate CPT by having different particle and antiparticle masses must be nonlocal. 相似文献
9.
Ralf Lehnert 《Hyperfine Interactions》2013,215(1-3):25-30
Lorentz and CPT invariance are among the symmetries that can be investigated with ultrahigh precision in subatomic physics. Being spacetime symmetries, Lorentz and CPT invariance can be violated by minuscule amounts in many theoretical approaches to underlying physics that involve novel spacetime concepts, such as quantized versions of gravity. Regardless of the underlying mechanism, the low-energy effects of such violations are expected to be governed by effective field theory. This talk provides a survey of this idea and includes an overview of experimental efforts in the field. 相似文献
10.
A. D. Dolgov 《Physics of Atomic Nuclei》2010,73(4):588-592
General features of generation of the cosmological charge asymmetry in CPT noninvariant world are discussed. If the effects of CPT violationmanifest themselves only inmass differences of particles and antiparticles, the baryon asymmetry of the Universe hardly can be explained solely by breaking of CPT invariance. However, CPT noninvariant theories may lead to a new effect of distorting the usual equilibrium distributions. If this takes place, CPT violation may explain the baryon asymmetry of the Universe. 相似文献
11.
F. Levi A. Godone J. Vanier S. Micalizio G. Modugno 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,12(1):53-59
The paper is concerned with the line shapes of resonance phenomena observed in Coherent Population Trapping (CPT) applied
to alkali atoms in a cell containing a buffer gas. Significant asymmetries and departures from a Lorentzian shape have been
observed in connection with the measurement of dark lines and CPT maser emission profiles. Measurements are reported as a
function of the power and frequency tuning of the laser used to create the CPT phenomenon. The paper reports on different
experimental conditions and a comparison between theory and experiments is made for the cases of cesium and rubidium in a
buffer gas.
Received 3 March 2000 and Received in final form 10 April 2000 相似文献
12.
We analyze an approximate solution to the Dirac equation for an electron in a central potential, in particular, in a Coulomb potential, when Lorentz invariance is violated. A quasi-relativistic approximation for the Dirac equation in an external field has been derived. The directivity pattern of spontaneous emission for a polarized hydrogen atom has been found to be asymmetric. 相似文献
13.
We present a class of interacting nonlocal quantum field theories, in which the CPT invariance is violated while the Lorentz invariance is present. This result rules out a previous claim in the literature that the CPT violation implies the violation of Lorentz invariance. Furthermore, there exists the reciprocal of this theorem, namely that the violation of Lorentz invariance does not lead to the CPT violation, provided that the residual symmetry of Lorentz invariance admits the proper representation theory for the particles. The latter occurs in the case of quantum field theories on a noncommutative space–time, which in place of the broken Lorentz symmetry possesses the twisted Poincaré invariance. With such a CPT-violating interaction and the addition of a C-violating (e.g., electroweak) interaction, the quantum corrections due to the combined interactions could lead to different properties for the particle and antiparticle, including their masses. 相似文献
14.
15.
J. Piekarewicz 《The European Physical Journal A - Hadrons and Nuclei》2007,32(4):537-541
The neutron radius of a heavy nucleus is a fundamental nuclear-structure observable that remains elusive. Progress in this
arena has been limited by the exclusive use of hadronic probes that are hindered by large and controversial uncertainties
in the reaction mechanism. The parity radius experiment at the Jefferson Laboratory offers an attractive electro-weak alternative
to the hadronic program and promises to measure the neutron radius of 208Pb accurately and model independently via parity-violating electron scattering. In this contribution we examine the far-reaching
implications that such a determination will have in areas as diverse as nuclear structure, atomic parity violation, and astrophysics. 相似文献
16.
We comment on CP, T and CPT violation in the light of interesting new data from the CPLEAR and KTeV Collaborations on neutral kaon decay asymmetries. Other recent data from the CPLEAR experiment, constraining possible violations of CPT and the ΔS=ΔQ rule, exclude the possibility that the semileptonic-decay asymmetry AT measured by CPLEAR could be solely due to CPT violation, confirming that their data constitute direct evidence for T violation. The CP-violating asymmetry in KL→e−e+π−π+ recently measured by the KTeV Collaboration does not by itself provide direct evidence for T violation, but we use it to place new bounds on CPT violation. 相似文献
17.
We investigate the sensitivities of future neutrino oscillation experiments for measuring the neutrino mass squared differences and leptonic mixing angles independently with neutrinos and anti-neutrinos. We update the expected sensitivities of Neutrino Factories to the “atmospheric” (anti-)neutrino parameters using an optimized setup. A dedicated β-Beam facility, in combination with a SPMIN reactor experiment, could give excellent sensitivities also to the “solar” parameters, for neutrinos and anti-neutrinos respectively. A signal of a different mass matrix for neutrinos and anti-neutrinos would imply CPT violation and non-locality of the underlying particle theory. 相似文献
18.
Adamson P Auty DJ Ayres DS Backhouse C Barr G Barrett WL Bishai M Blake A Bock GJ Boehnlein DJ Bogert D Bower C Budd S Cavanaugh S Cherdack D Childress S Choudhary BC Coelho JA Cobb JH Coleman SJ Corwin L Cravens JP Cronin-Hennessy D Danko IZ de Jong JK Devenish NE Diwan MV Dorman M Escobar CO Evans JJ Falk E Feldman GJ Frohne MV Gallagher HR Gomes RA Goodman MC Gouffon P Gran R Grant N Grzelak K Habig A Harris D Harris PG Hartnell J Hatcher R Himmel A Holin A Huang X Hylen J Ilic J Irwin GM 《Physical review letters》2010,105(15):151601
We searched for a sidereal modulation in the MINOS far detector neutrino rate. Such a signal would be a consequence of Lorentz and CPT violation as described by the standard-model extension framework. It also would be the first detection of a perturbative effect to conventional neutrino mass oscillations. We found no evidence for this sidereal signature, and the upper limits placed on the magnitudes of the Lorentz and CPT violating coefficients describing the theory are an improvement by factors of 20-510 over the current best limits found by using the MINOS near detector. 相似文献
19.
Canè F Bear D Phillips DF Rosen MS Smallwood CL Stoner RE Walsworth RL Kostelecký VA 《Physical review letters》2004,93(23):230801
A search for an annual variation of a daily sidereal modulation of the frequency difference between colocated 129Xe and 3He Zeeman masers sets a stringent limit on boost-dependent Lorentz and CPT violation involving the neutron, consistent with no effect at the level of 150 nHz. In the framework of the general standard-model extension, the present result provides the first clean test for the fermion sector of the symmetry of spacetime under boost transformations at a level of 10(-27) GeV. 相似文献
20.
Bennett GW Bousquet B Brown HN Bunce G Carey RM Cushman P Danby GT Debevec PT Deile M Deng H Deninger W Dhawan SK Druzhinin VP Duong L Efstathiadis E Farley FJ Fedotovich GV Giron S Gray FE Grigoriev D Grosse-Perdekamp M Grossmann A Hare MF Hertzog DW Huang X Hughes VW Iwasaki M Jungmann K Kawall D Kawamura M Khazin BI Kindem J Krienen F Kronkvist I Lam A Larsen R Lee YY Logashenko I McNabb R Meng W Mi J Miller JP Mizumachi Y Morse WM Nikas D Onderwater CJ Orlov Y Ozben CS Paley JM Peng Q 《Physical review letters》2008,100(9):091602
The spin precession frequency of muons stored in the (g-2) storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for a nonzero delta omega a(=omega a mu+ - omega a mu-) and a sidereal variation of omega a mu+/-). No significant effect is found, and the following limits on the standard-model extension parameters are obtained: bZ = -(1.0+/-1.1) x 10(-23) GeV; (m mu dZ0 + HXY)=(1.8+/-6.0) x 10(-23) GeV; and the 95% confidence level limits b perpendicular mu+ <1.4 x 10(-24) GeV and b perpendicular mu- <2.6 x 10(-24) GeV. 相似文献