SYMETRIES IN SUBATOMIC PHYSICS: 3rd International Symposium

Latest experimental information on
View Description Hide DescriptionWe review the latest experimental results in searching for “direct” CPviolation by measuring the CPviolating parameters in neutral kaon decays. Recent result from FermilabKTeV and new preliminary result from CERNNA48 are presented. Both experiments, though using very different techniques, have now performed very well by collecting millions of events for all four relevant decay modes of to and simultaneously. The current world average on this important measurement is with a establishing the existence of “direct” CPviolation. The experimental status of such crucial measurements and the future prospects are also discussed here.

CP violation 2000: Status and perspectives
View Description Hide DescriptionWe summarize the present status of CP violation discussing in particular the standard analysis of the unitarity triangle and the ratio including most recent developments. The perspectives in this field include in particular B decays, rare K decays such as and and the improved standard analysis of the unitarity triangle through the measurement of mixing.

Latest results from SuperKamiokande
View Description Hide DescriptionRecent data from SuperKamiokande on solar and atmospheric neutrinos and their constraints on the neutrino mass and mixing are presented. Also results on proton decay searches are presented.

Additional isospinbreaking effects in
View Description Hide DescriptionIsospinbreaking effects, in particular those associated with electroweakpenguin contributions and mixing, have long been known to affect the Standard Model prediction of in a significant manner. We have found an heretofore unconsidered isospinviolating effect of importance; namely, the ud quark mass difference can spawn components in the matrix elements of the gluonic penguin operators. Using chiral perturbation theory and the factorization approximation for the hadronic matrix elements, we find within a specific model for the lowenergy constants that we can readily accommodate an increase in by a factor of two.

Isospin breaking in the extraction of isovector and isoscalar spectral functions from
View Description Hide DescriptionA finite energy sum rule (FESR) analysis of the isospinbreaking vector current correlator is used to determine the isospinbreaking electromagnetic (EM) decay constants of the lowlying vector mesons. These results are used to evaluate the corrections required to extract the flavor diagonal 33 and 88 resonance contributions from the full resonance EM contributions to the EM spectral function. A large (∼15%) correction is found in the case of the ω contribution to the isoscalar spectral function. The implications of these results for sum rules based on the isovectorisoscalar spectral difference are considered.

Neutrino mixing and CP violation in matter
View Description Hide DescriptionWithin the framework of three lepton families I present a transparent analytical relationship between the neutrino mixing and CPviolating parameters in vacuum and those in matter. Such a model and parametrizationindependent result will be particularly useful to recast the fundamental lepton flavor mixing matrix from the future longbaseline neutrino experiments.

Tritium decay, neutrino mixing and neutrino interactions
View Description Hide DescriptionRecent Tritium beta decay experiments continue to exhibit an excess of counts near the end point. The representation of the data in terms of the extracted mass squared can be reproduced by allowing interference between the Standard Model VA current and other Lorentz currents allowed by existing experimental limits. This is true only if the electron antineutrino is nearly, but not exactly, a single mass eigenstate with a mixing probability to other mass eigenstates of the order of a few parts per thousand, and if the mass of that eigenstate is a few electron volts. In conjunction with double beta decay constraints, this precludes a solitary Majorana neutrino in the electron family. Combining this with solar neutrino results leads to pseudoDirac neutrinos and implies that neutral current events in SNO will suffer the same suppression as charge current events.

Constraints on a parityeven/timereversalodd interaction
View Description Hide DescriptionTimeReversalInvariance nonconservation has for the first time been unequivocally demonstrated in a direct measurement, one of the results of the CPLEAR experiment. What is the situation then with regard to timereversalinvariance nonconservation in systems other than the neutral kaon system? Two classes of tests of timereversalinvariance need to be distinguished: the first one deals with parity violating (Podd)/timereversalinvariance nonconserving (Todd) interactions, while the second one deals with Peven/Todd interactions (assuming CPT conservation this implies Cconjugation nonconservation). Limits on a Podd/Todd interaction follow from measurements of the electric dipole moment of the neutron. This in turn provides a limit on a Podd/Todd pionnucleon coupling constant which is times the weak interaction strength. Limits on a Peven/Todd interaction are much less stringent. The better constraint stems also from the measurement of the electric dipole moment of the neutron. Of all the other tests, measurements of chargesymmetry breaking in neutronproton elastic scattering provide the next better constraint. The latter experiments were performed at TRIUMF (at 477 and 347 MeV) and at IUCF (at 183 MeV). Weak decay experiments (the transverse polarization of the muon in and the transverse polarization of the positrons in polarized muon decay) have the potential to provide comparable or possibly better constraints.

What can we learn from QED at large couplings?
View Description Hide DescriptionIn order to understand QCD at the energies relevant to hadronic physics one requires analytical methods for dealing with relativistic gauge field theories at large couplings. Strongly coupled quenched QED provides an ideal laboratory for the development of such techniques, in particular as many calculations suggest that—like QCD—this theory has a phase with broken chiral symmetry. In this talk we report on a nonperturbative variational calculation of the electron propagator within quenched QED and compare results to those obtained in other approaches. We find surprising differences among these results.

CP violation in SM vs new physics
View Description Hide DescriptionI discuss CP violation in comparing the standard model expectations with what could happen in new physics scenarios. I point out that Fermilab experiment E871 is sensitive to some of these scenarios.

Quark mixing angles and CPviolating phase from flavor permutational symmetry breaking
View Description Hide DescriptionDifferent Ansätze for the breaking of flavor permutational symmetry according to give different Hermitian mass matrices of the same modified Fritzsch type, which differ in the symmetry breaking pattern. A clear and precise indication on the preferred symmetry breaking scheme is obtained from a fit of the predicted to the experimentally determined absolute values of the elements of the CKM matrix. The preferred scheme leads to simple mass textures and allows us to compute the CKM mixing matrix, the Jarlskog invariant J, and the three inner angles of the unitarity triangle in terms of four quark mass ratios and only two free parameters: Z and the CP violating phase Φ. Excellent agreement with the experimentally determined absolute values of the entries in the CKM matrix is obtained for and The corresponding computed values of the Jarlskog invariant and the inner angles are and in very good agreement with current data on CP violation in the kaonantikaon system and oscillations in the BantiB system. It is also shown that the theoretical mixing matrix derived from the breaking of the flavor permutational symmetry and the standard parametrization advocated by the Particle Data Group are equivalent, up to a redefinition of the unobservable phases of the quark fields in the mass representation. From here, we derive exact explicit expressions for the three mixing angles and the CP violating phase in terms of the quark mass ratios and the parameters and characterizing the preferred symmetry breaking pattern. The predicted values for the CP violating phase and the mixing angles are: and which coincide almost exactly with the central values of the experimentally determined quantities.

Atomic theory and tests of the Standard Model in atomic experiments
View Description Hide DescriptionMeasurements of the weak charge characterizing the strength of the electronnucleon weak interaction provide tests of the Standard Model and a way of searching for new physics beyond the Standard Model. Atomic experiments give limits on the extra Zboson, leptoquarks, composite fermions, and radiative corrections produced by particles that are predicted by new theories. To extract the accurate value of the weak charge from atomic experiments one has to perform high precision atomic calculations of the PNC effects.

Precision tests of the Standard Model at electron colliders
View Description Hide DescriptionWe review electroweak physics studies in highenergy collisions at CERN and SLAC. Studies of couplings of the boson to many of the fundamental fermions are now quite detailed, and those of the bosons are well under way. Sensitivity to radiative corrections due to the massive top quark, the as yet undiscovered Higgs boson, and new physics at the TeV scale has been achieved. The Standard Model is consistent with all data, although further studies are indicated in several areas. In the absence of new physics, the Higgs mass is limited to <188 GeV/c^{2} at 95% C.L.

Lorentz and CPT tests in atomic systems
View Description Hide DescriptionA review of Lorentz and CPT tests performed in atomic systems is presented. A theoretical framework extending QED in the context of the standard model is used to analyze a variety of systems. Experimental signatures of possible Lorentz and CPT violation in these systems are investigated. Estimated bounds attainable in future experiments and actual bounds obtained in recent experiments are given.

New clock comparison searches for Lorentz and CPT violation
View Description Hide DescriptionWe present two new measurements constraining Lorentz and CPT violation using the Zeeman maser and atomic hydrogen masers. Experimental investigations of Lorentz and CPT symmetry provide important tests of the framework of the standard model of particle physics and theories of gravity. The twospecies Zeeman maser bounds violations of CPT and Lorentz symmetry of the neutron at the level. Measurements with atomic hydrogen masers provide a clean limit of CPT and Lorentz symmetry violation of the proton at the level.

Charges, parity doublets and ParityNonConservation
View Description Hide DescriptionCharges and ParityNonConservation are two ingredients that, at present, are introduced by hand in the description of particles and their interactions. We elaborate on a suggestion which was made in the past by Landau and tends to relate them. Particles and their antiparticles are associated here to the parity partners appearing in a model with chiral and parity symmetry realized in the WignerWeyl mode, i.e. with parity doublets or, equivalently, states of opposite chiral charges. Paritynonconservation in such a model is ascribed to the noncommutativity of the parity and the (chiral) charge operators, preventing one to have eigenstates of both at the same time.

Enhancement of parity and time invariance violation in heavy atoms
View Description Hide DescriptionParity (P) and time (T) invariance violating effects are enhanced in atoms with close states of opposite parity, large nuclear charge Z, and collective P, Todd nuclear moments. We have performed calculations of the atomic electric dipole moment (EDM) induced in radium by the electron EDM and the nuclear magnetic quadrupole and Schiff moments. We have also calculated the effects of parity nonconservation in radium produced by the nuclear anapole moment and the nuclear weak charge. Our results show that the values of parity and time invariance violating effects in radium are much larger than those considered so far in other atoms.

Symmetry motivated estimation of nucleon deltaexcitation
View Description Hide DescriptionLongrange correlations in nuclear excitations and binding energies are compared with empirical relations in particle mass spectrum.

Pionbaryon couplings and SU(3)
View Description Hide DescriptionWe have extended and applied a general QCD parameterization method to the emission of pions from baryons. We use it to calculate the strength and sign of the coupling of pions to the octet and decuplet of baryons. We first use SU(3) and then include SU(3)breaking effects.

Direct CP violation in charmed hadron decays via mixing
View Description Hide DescriptionWe study direct CP violation in the charmed hadron decays and via mixing. The CP violation parameter depends on the effective parameter, which is relevant to hadronization dynamics of each decay channel. It is found that for fixed the CP violation parameter reaches its maximum value when the invariant mass of the pair is in the vicinity of the ω resonance. For most of the parameter space explored the CP violating asymmetry is of order However, over a small range, and the asymmetries for and (respectively) can exceed 1%at the cost of a small branching ratio, and respectively.