New Physics and CP Violation in Hyperon Nonleptonic Decays

The sum of the CP-violating asymmetries A(Lambda_-^0) and A(Xi_-^-) in hyperon nonleptonic decays is presently being measured by the E871 experiment. We evaluate contributions to the asymmetries induced by chromomagnetic-penguin operators, whose coefficients can be enhanced in certain models of new physics. Incorporating recent information on the strong phases in Xi->Lambda pi decay, we show that new-physics contributions to the two asymmetries can be comparable. We explore how the upcoming results of E871 may constrain the coefficients of the operators. We find that its preliminary measurement is already better than the epsilon parameter of K-Kbar mixing in bounding the parity-conserving contributions.Comment: 12 pages, 2 figure

The Uncertainty in Newton's Constant and Precision Predictions of the Primordial Helium Abundance

The current uncertainty in Newton's constant, G_N, is of the order of 0.15%. For values of the baryon to photon ratio consistent with both cosmic microwave background observations and the primordial deuterium abundance, this uncertainty in G_N corresponds to an uncertainty in the primordial 4He mass fraction, Y_P, of +-1.3 x 10^{-4}. This uncertainty in Y_P is comparable to the effect from the current uncertainty in the neutron lifetime, which is often treated as the dominant uncertainty in calculations of Y_P. Recent measurements of G_N seem to be converging within a smaller range; a reduction in the estimated error on G_N by a factor of 10 would essentially eliminate it as a source of uncertainty in the calculation of the primordial 4He abundance.Comment: 3 pages, no figures, fixed typos, to appear in Phys. Rev.

πΞ\pi\Xi phase shifts and CP Violation in Ω→πΞ{\Omega\to\pi\Xi} Decay

In the study of CP violation signals in {\O}\to\pi\Xi nonleptonic decays, the strong $J$=3/2 $P$ and $D$ phase shifts for the $\pi\Xi$ final-state interactions are needed. These phases are calculated using an effective Lagrangian model, including $\Xi$, $\Xi^*$(1530), $\rho$ and the $\sigma$-term, in the intermediate states. The $\sigma$-term is calculated in terms of the scalar form factor of the baryon.Comment: 6 pages, 2 figure

Recoil Order Chiral Corrections to Baryon Octet Axial Currents and Large NcN_c QCD

We compute the chiral corrections to octet baryon axial currents through ${\cal O}(p^3)$ in heavy baryon chiral perturbation theory, including both octet and decuplet baryon intermediate states. We include the latter in a consistent way by using the small scale expansion. We find that, in contrast to the situation at ${\cal O}(p^2)$, there exist no cancellations between octet and decuplet contributions at ${\cal O}(p^3)$. Consequently, the ${\cal O}(p^3)$ corrections spoil the expected scaling behavior of the chiral expansion. We discuss this result in terms of the $1/N_c$ expansion. We also consider the implications for determination of the strange quark contribution to the nucleon spin from polarized deep inelastic scattering data.Comment: 7 page

In-Plane Gamma-Ray Coincidence Correlations for the 12-C(pol.p'γ)12-C

This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation

The current status of electric dipole moments of diamagnetic atoms which involves the synergy between atomic experiments and three different theoretical areas -- particle, nuclear and atomic is reviewed. Various models of particle physics that predict CP violation, which is necessary for the existence of such electric dipole moments, are presented. These include the standard model of particle physics and various extensions of it. Effective hadron level combined charge conjugation (C) and parity (P) symmetry violating interactions are derived taking into consideration different ways in which a nucleon interacts with other nucleons as well as with electrons. Nuclear structure calculations of the CP-odd nuclear Schiff moment are discussed using the shell model and other theoretical approaches. Results of the calculations of atomic electric dipole moments due to the interaction of the nuclear Schiff moment with the electrons and the P and time-reversal (T) symmetry violating tensor-pseudotensor electron-nucleus are elucidated using different relativistic many-body theories. The principles of the measurement of the electric dipole moments of diamagnetic atoms are outlined. Upper limits for the nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained combining the results of atomic experiments and relativistic many-body theories. The coefficients for the different sources of CP violation have been estimated at the elementary particle level for all the diamagnetic atoms of current experimental interest and their implications for physics beyond the standard model is discussed. Possible improvements of the current results of the measurements as well as quantum chromodynamics, nuclear and atomic calculations are suggested.Comment: 46 pages, 19 tables and 16 figures. A review article accepted for EPJ

Determination of alphaS from Hadronic Event Shapes in e+e- Annihilation at 192 < sqrt(s) < 208 GeV

Results are presented from a study of the structure of high energy hadronic events recorded by the L3 detector at sqrt(s)>192 GeV. The distributions of several event shape variables are compared to resummed O(alphaS^2) QCD calculations. We determine the strong coupling constant at three average centre-of-mass energies: 194.4, 200.2 and 206.2 GeV. These measurements, combined with previous L3 measurements at lower energies, demonstrate the running of alphaS as expected in QCD and yield alphaS(mZ) = 0.1227 +- 0.0012 +- 0.0058, where the first uncertainty is experimental and the second is theoretical

B decays and models for CP violation

The decay modes $B$ to $\pi\pi$, $\psi K_S$, $K^- D$, $\pi K$ and $\eta K$ are promising channels to study the unitarity triangle of the CP violating CKM matrix. In this paper I study the consequences of these measurements in the Weinberg model. I show that using the same set of measurements, the following different mechanisms for CP violation can be distinguished: 1) CP is violated in the CKM sector only; 2) CP is violated spontaneously in the Higgs sector only; And 3) CP is violated in both the CKM and Higgs sectors.Comment: 18 pagers, Revtex, Four compressed figures. Some typos in the figure captions are correcte

CP Violation in Top Quark Pair Production at Hadron Colliders

CP violating effects in top quark pair production at the future 2 TeV $p\bar p$ Tevatron and 14 TeV $pp$ LHC colliders are investigated. We study three kinds of CP violating sources:the supersymmetric CP-odd phase of the stop trilinear soft breaking term: $arg(A_t)$, the CP-odd parameter in two-Higgs doublet extensions of the standard model(2HDM), and the model-independent top quark chromoelectric dipole moment(CEDM), respectively. Optimal observables as well as simple observables are used. We find that it is possible to observe CP violating effects from $arg(A_t)$ in top quark pair production at the 2 TeV Tevatron with $\sim 30fb^{-1}$ integrated luminosity when $m_{\tilde{g}}\sim 200$ GeV. If the experimental systematic errors are sufficient small, the LHC with $\sim 150fb^{-1}$ can put a limit of order $10^{-1}$ on the phase $arg(A_t)$ and the CP-odd parameter in 2HDM by using optimal observables. The CEDM of the top quark can be measured to an accuracy of $10^{-18} cm g_s$ at the Tevatron and few $\times 10^{-20} cm g_s$ at the LHC.Comment: 28 pages,3 figures, 38 ref

Effects of sleep deprivation on neural functioning: an integrative review

Sleep deprivation has a broad variety of effects on human performance and neural functioning that manifest themselves at different levels of description. On a macroscopic level, sleep deprivation mainly affects executive functions, especially in novel tasks. Macroscopic and mesoscopic effects of sleep deprivation on brain activity include reduced cortical responsiveness to incoming stimuli, reflecting reduced attention. On a microscopic level, sleep deprivation is associated with increased levels of adenosine, a neuromodulator that has a general inhibitory effect on neural activity. The inhibition of cholinergic nuclei appears particularly relevant, as the associated decrease in cortical acetylcholine seems to cause effects of sleep deprivation on macroscopic brain activity. In general, however, the relationships between the neural effects of sleep deprivation across observation scales are poorly understood and uncovering these relationships should be a primary target in future research