Ital CPT Research Articles

Bounding CPT violation in the neutral B system.

The feasibility of placing bounds on {ital CPT} violation from experiments with neutral {ital B} mesons is examined. We consider situations with uncorrelated mesons and ones with either unboosted or boosted correlated mesons. Analytical expressions valid for small {ital T}- and {ital CPT}-violating parameters are presented for time-dependent and time-integrated decay rates, and various relevant asymmetries are derived. We use Monte Carlo simulations to model experimental conditions for a plausible range of {ital CPT}-violating parameters. The treatment uses realistic data incorporating background effects, resolutions, and acceptances for typical detectors at CERN LEP, CESR, and the future {ital B} factories. Presently, there are no bounds on {ital CPT} violation in the {ital B} system. We demonstrate that limits of order 10{percent} on {ital CPT} violation can be obtained from data already extant, and we determine the {ital CPT} reach attainable within the next few years. {copyright} {ital 1996 The American Physical Society.}

CPT tests in the neutral kaon system.

Fermilab experiment E773 has measured the phases {Phi}{sub +{minus}}=43.53{degree}{plus_minus}0.97{degree} and {Phi}{sub 00}{minus}{Phi}{sub +{minus}}=0.62{degree}{plus_minus}1.03{degree} of the {ital CP} violating parameters {eta}{sub +{minus}} and {eta}{sub 00} from interference in the decay of neutral kaons into two charged or neutral pions from a pair of regenerators. New measurements of the {ital K}{sub {ital L}}-{ital K}{sub {ital S}} mass difference and the {ital K}{sub {ital S}} lifetime are also given. These results test {ital CPT} symmetry and show no evidence for a violation.

New test of the equivalence principle for the antiproton.

New tests of the weak equivalence principle for the antiproton and other hadrons are derived from a recent test of {ital CPT} symmetry in the {ital K}{sup 0}{ital {bar K}} {sup 0} system using the MIT bag model.

CP violation in inclusive and exclusive charmless B decays.

Absorptive parts in penguin amplitudes lead to {ital CP}-violating partial rate asymmetries in {ital B}-meson decays. A careful study of the inclusive process reveals a subtlety in the implementation of this mechanism. Because of (1) the smallness of {ital V}{sub {ital u}{ital b}}/{ital V}{sub {ital c}{ital b}}, (2) the fact that {alpha}{sub {ital s}}({ital m}{sub {ital b}}) is not too small, and (3) the kinematic suppression of {ital c{bar c}} absorptive contribution, {ital O}({alpha}{sub {ital s}}{sup 2}) effects have to be kept consistently. We find a strong correlation between the {ital CP} rate asymmetries of the {ital b}{r arrow}{ital su{bar u}} mode and the purely loop-induced {ital b}{r arrow}{ital sd{bar d}} and {ital ss{bar s}} modes, which is a consequence of the constraints of {ital CPT} invariance. The semi-inclusive charmless {ital b}{r arrow}{ital su{bar u}} decay rate asymmetry is therefore negligibly small. With the (semi-)inclusive result as a guide, we estimate the rates and {ital CP} asymmetries for several exclusive several exclusive modes. Keeping only the perturbative, penguin-induced absorptive part, one finds that the modes due to {ital b}{r arrow}{ital su{bar u}} (e.g., {ital B}{sup {minus}}{r arrow}{ital K}{sup {minus}}{pi}{sup 0}) could have {ital CP} rate asymmetries opposite in sign withmore » respect to pure penguin modes (such as {ital B}{sup {minus}}{r arrow}{ital K}{sup {minus}}{phi}), contrary to naive expectations. Charmless {ital b}{r arrow}{ital d} transitions are also discussed. We emphasize that exclusive {ital b}{r arrow}{ital d} modes (such as {ital B}{sup {minus}}{r arrow}{ital K}{sup {minus}}{ital K}{sub {ital S}}) may be more promising for {ital CP} studies within the standard model. Many uncertainties and problems related to penguin processes are discussed and assessed in detail.« less

Decay and evolution of the neutral kaon.

The time evolution of the neutral-kaon complex is investigated, making use of the constraints of {ital CPT} invariance, a non-negative energy spectrum, and the corrections to the Lee-Oehme-Yang phenomenological theory. Some numerical estimates are made which are compared with the work of Khalfin, which stimulated the present work.

Direct tests of CPT and T invariance in the neutral-kaon mass matrix.

I suggest a possible way of measuring the {ital T}- and {ital CPT}-violating parameters in the neutral-kaon mass matrix, which makes use of their influence on, respectively, the difference of normalization and the difference of shape of the decay curves, to an arbitrary channel {ital c} of kaons and antikaons. This method is alternative to the direct study of the neutral-kaon oscillations. Both require kaon beams with well-defined strangeness.

Test of CPT symmetry through a determination of the difference in the phases of eta 00 and eta +- in K-->2 pi decays.

Data collected by the E731 experiment at Fermilab were used to search for {ital CPT} violation in {ital K}{sup 0}{r arrow}{pi}{pi} decays by measuring the difference {Delta}{phi} between the phases of the {ital CP}-violating parameters {eta}{sub 00} and {eta}{sub +{minus}}. Our result, {Delta}{phi}={minus}0.3{degree}{plus minus}2.4{degree}{plus minus}1.2{degree}, where the first error is statistical and the second systematic, is consistent with {ital CPT} symmetry.

Multipole expansion of conserved tensor currents and the number of form factors.

We develop a formalism for defining and studying the form factors which describe the coupling of a spin-{ital J} particle through a conserved tensor current to a spin-{ital S} boson. For {ital S}=2, these form factors are the single-graviton gravitational form factors. We investigate the behavior of the various form factors under {ital C}, {ital P}, {ital T}, and {ital CPT} and classify them accordingly. We show that under {ital CPT} invariance all the multipoles of the mass distribution are the same for a particle and its antiparticle. We also show that in a quantum theory of gravity the coupling of a particle to the graviton is in general different from that of its antiparticle. Only when {ital P} and {ital T} are both valid symmetries of the underlying theory do a particle and its antiparticle couple identically to the graviton. The number of form factors for arbitrary {ital J} and {ital S} is given. We show that a massive Majorana particle (a {ital CPT} self-conjugate particle) coupling to an odd-spin boson possesses only anapole moments. Massless Majorana particles with spin{ne}1/2 have no single-photon electromagnetic form factors while the ones with spin{ne}1/2, 1, or 3/2 have no interactions with amore » spin-3 boson; this applies to the graviton ({ital J}=2, {ital S}=1,3) and to the massless gravitino ({ital J}=3/2, {ital S}=1). Our results also apply to extended objects (nuclei, . . .) in the low-energy limit.« less

Isospin incursion into CPT theorem in non-Abelian gauge theory.

The {ital CPT} theorem is reexamined in non-Abelian gauge theory where there is {ital spin} {ital from} {ital isospin}. Jost's proof can be adapted with the substitution of {ital k} spin in place of the usual {ital j} spin where the {ital total} angular momentum is now {bold K}={bold J}+{bold I}. Possible implications on the parity eigenvalues are discussed. If the parity is given by {ital P}{prime}=({minus}1){sup {ital l}}, where {ital l}({ital l}+1) is the eigenvalue of {bold L}{sup 2} with {bold L}={bold r}{times}{bold p}+{bold I}, rather than {ital P}=({minus}1){sup {ital l}{sub 0}}, where {ital l}{sub 0}(l{sub 0}+1) is the eigenvalue of {bold L}{sub 0}{sup 2} with {bold L}{sub 0}={bold r}{times}{bold p}, then a modified {ital CPT} theorem holds.