Search results for "cpt"
showing 10 items of 62 documents
Direct test of time reversal symmetry in the entangled neutral kaon system at a phi-factory
2013
We present a novel method to perform a direct T (time reversal) symmetry test in the neutral kaon system, independent of any CP and/or CPT symmetry tests. This is based on the comparison of suitable transition probabilities, where the required interchange of in out states for a given process is obtained exploiting the Einstein-Podolski-Rosen correlations of neutral kaon pairs produced at a phi-factory. In the time distribution between the two decays, we compare a reference transition like the one defined by the time-ordered decays (l(-), pi pi) with the T-conjugated one defined by (3 pi(0), l(+)). With the use of this and other T-conjugated comparisons, the KLOE-2 experiment at DA Phi NE co…
Thousandfold improvement in the measured antiproton mass
1990
Comparisons of antiproton and proton cyclotron frequencies yield the ratio of inertial masses M(p¯)/M(p)=0.999 999 977 ±0.000 000 042. The fractional uncertainty of 4×10−8 is 1000 times more accurate than previous measurements of this ratio using exotic atoms and is the most precise test of CPT invariance with baryons. Independent comparisons to electrons yield the mass ratios M(p¯)/M(e−)=1836.152 660±0.000 083 and M(p)/M(e−) =1836.152 680±0.000 088. Cryogenic antiprotons (near 4 K) stored in a Penning trap for 2 months establish directly a lifetime greater than 3.4 months.
Towards a direct measurement of the g-factor of a single isolated protonThis paper was presented at the International Conference on Precision Physics…
2011
Our Penning trap experiment aims at a direct high-precision measurement of the proton g-factor. We present the experimental setup and the measurement technique using the continuous Stern-Gerlach effect. Recent test measurements with a single proton stored in a Penning trap with a strong magnetic bottle and a new toroidal detection system are discussed. For a stringent test of the CPT symmetry the described technique can also be applied to the antiproton.
Search ForT,CP, andCPTViolation inB0−B¯0Mixing with Inclusive Dilepton Events
2006
The authors report the results of a search for T, CP and CPT violation in B{sup 0}-{bar B}{sup 0} mixing using an inclusive dilepton sample collected by the BABAR experiment at the PEP-II B Factory. Using a sample of 232 million B{bar B} pairs, with a simultaneous likelihood fit of the same-sign and opposite-sign dileptons, they measure the T and Cp violation parameter |q/p|-1 = (-0.8 {+-} 2.7(stat.) {+-} 1.9(syst.)) x 10{sup -3}, and the CPT and CP parameters Im z = (-13.9 {+-} 7.3(stat.) {+-} 3.2(syst.)) x 10{sup -3} and {Delta}{Lambda} x Re z = (-7.1 {+-} 3.9(stat.) {+-} 2.0(syst.)) x 10{sup -3} ps{sup -1}. The statistical correlation between the measurements of Im z and {Delta}{Lambda} …
Search forCPTand Lorentz Violation inB0−B¯0Oscillations with Dilepton Events
2008
We report results of a search for CPT and Lorentz violation in B{sup 0}-{bar B}{sup 0} oscillations using inclusive dilepton events from 232 million {Upsilon}(4S) {yields} B{bar B} decays recorded by the BABAR detector at the PEP-II B Factory at SLAC. We find 2.8{sigma} 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 {Delta}a{sub {mu}} in the general Lorentz-violating standard-model extension. The spectral powers for variations in z over the frequency range 0.26 year{sup -1} to 2.1 day{sup -1} are also compatible with no signal.
Models of CP Violation
2003
After the discovery of CP violation in K decay, a host of theoretical models was proposed to allocate this phenomenon to known interactions. Assuming CPT invariance of all interactions, the observed CP-violating effects in K decay imply also T violation. In general, with CPT invariance, there are four combinations of violations possible to be treated in this chapter
Supersymmetry does not imply mass degeneracy
2004
Abstract It is commonly believed that unbroken supersymmetry (SUSY) implies that all members of a supermultiplet have the same mass. We demonstrate that this is not true, by exhibiting a simple counterexample. We employ the formalism of homeotic fermions, in a simple model where CPT conjugate fermions have different masses. This model can be supersymmetrized to a hypermultiplet of fields which form a representation of the conventional N=2 SUSY algebra. Nevertheless, CPT conjugate states in this hypermultiplet have different masses. These surprising results do not violate either the CPT theorem or the Haag–Lopuszanski–Sohnius theorem.
The anomalous magnetic moment of positive and negative muons
1977
Abstract The anomalous g -factor a ≡ ( g −2)/2 has been measured for muons of both charges in the Muon Storage Ring at CERN. The two results, a μ + = 1165910(12) × 10 −9 and a μ − = 1165936(12) × 10 −9 , are in good agreement with each other, and combine to give a mean a μ = 1165922(9) × 10 −9 , which is very close to the most recent theoretical prediction 1165921(10) × 10 −9 . For the experimental results, the total statistical and systematic error is given. The measurements thus confirm the remarkable QED calculation plus hadronic contribution, and serve as a precise verification of the CPT theorem for muons.
New physics vs new paradigms: distinguishing CPT violation from NSI
2019
Our way of describing Nature is based on local relativistic quantum field theories, and then CPT symmetry, a natural consequence of Lorentz invariance, locality and hermiticity of the Hamiltonian, is one of the few if not the only prediction that all of them share. Therefore, testing CPT invariance does not test a particular model but the whole paradigm. Current and future long baseline experiments will assess the status of CPT in the neutrino sector at an unprecedented level and thus its distinction from similar experimental signatures arising from non-standard interactions is imperative. Whether the whole paradigm is at stake or just the standard model of neutrinos crucially depends on th…
A parts-per-billion measurement of the antiproton magnetic moment
2017
The magnetic moment of the antiproton is measured at the parts-per-billion level, improving on previous measurements by a factor of about 350. Comparing the fundamental properties of normal-matter particles with their antimatter counterparts tests charge–parity–time (CPT) invariance, which is an important part of the standard model of particle physics. Many properties have been measured to the parts-per-billion level of uncertainty, but the magnetic moment of the antiproton has not. Christian Smorra and colleagues have now done so, and report that it is −2.7928473441 ± 0.0000000042 in units of the nuclear magneton. This is consistent with the magnetic moment of the proton, 2.792847350 ± 0.0…