126290118
QCD radiative corrections to J/ψ leptonic decay by using the scalar-integral reduction method
116621787
Polarization of prompt J/ in proton-proton collisions at RHIC
Within the framework of the nonrelativistic QCD (NRQCD) factorization approach, we compute the polarization of prompt J/{psi} produced at the Brookhaven's Relativistic Heavy-Ion Collider from proton-proton collisions at the center-of-momentum energy {radical}(s)=200 GeV. The perturbative contributions are computed at leading order in the strong coupling constant. The prediction reveals that the color-singlet contribution severely underestimates the PHENIX preliminary data for the differential cross section integrated over the rapidity range |y|<0.35 and its contribution is strongly transversely polarized, which disagrees with the PHENIX preliminary data. After including the color-octet contributions, we find that the NRQCD predictions for both the cross section and polarization over the transverse-momentum range 1.5 GeV<p{sub T}<5 GeV (1.5 GeV<p{sub T}<2 GeV) integrated over the rapidity range |y|<0.35 (1.2<|y|<2.2) agree with the data within errors.
26919092
A Measurement of the Michel Parameters in Leptonic Decays of the Tau
We have measured the spectral shape Michel parameters {rho} and {eta} using leptonic decays of the {tau}, recorded by the CLEO II detector. Assuming e-{mu} universality, we find {rho}{sub e{mu}}= 0.735 {+-} 0.013 {+-} 0.008 and {eta}{sub e{mu}} = 0.015 {+-} 0.061 {+-} 0.062, where the first error is statistical and the second systematic.
125995563
Double quarkonium production at the LHC
118538298
Exclusive heavy quarkonium + γ production from e+e-annihilation into a virtual photon
We compute the cross section for exclusive production of a photon associated with a heavy quarkonium H of charge-conjugation parity C=+1 from e{sup +}e{sup -} annihilation into a virtual photon at the center-of-momentum energy {radical}(s)=10.58 GeV. The nonrelativistic QCD factorization formulas for the differential and total cross sections are obtained at leading order in the strong coupling and in the relative velocity of the heavy quark in the quarkonium rest frame. The predicted cross sections for the S-wave spin-singlet cases are about 80 fb and 50 fb for H={eta}{sub c} and {eta}{sub c}(2S), respectively. Among P-wave spin-triplet charmonia, {chi}{sub c1} has a particularly large cross section of about 14 fb. The cross sections for bottomonium states {eta}{sub b} and {chi}{sub bJ} are about 3 fb. A rough estimate of the background reveals that the signal significances for charmonium processes are sufficiently large enough to be detected with ease with the integrated luminosities available at the present B factories.
124343131
Exclusive spin-2 glueball production associated with J/ψ from e +e- annihilation
119214237
The Solar-Type Contact Binary BX Pegasi Revisited
We present the results of new CCD photometry for the contact binary BX Peg, made during three successive months beginning on 2008 September. As do historical light curves, our observations display an O'Connell effect and the November data by themselves indicate clear evidence for very short-term brightness disturbance. For these variations, model spots are applied separately to the two data sets, Group I (Sep.-Oct.) and Group II (Nov.). The former is described by a single cool spot on the secondary photosphere and the latter by a two-spot model with a cool spot on the cool star and a hot one on either star. These are generalized manifestations of the magnetic activity of the binary system. Twenty light-curve timings calculated from Wilson-Devinney code were used for a period study, together with all other minimum epochs. The complex period changes of BX Peg can be sorted into a secular period decrease caused dominantly by angular momentum loss due to magnetic stellar wind braking, a light-travel time (LTT) effect due to the orbit of a low-mass third companion, and a previously unknown short-term oscillation. This last period modulation could be produced either by a second LTT orbit with a period of about 16 yr due to the existence of a fourth body, or by the effect of magnetic activity with a cycle length of about 12 yr.
119267267
CORONAL THICK TARGET HARD X-RAY EMISSIONS AND RADIO EMISSIONS
A distinctive class of hard X-ray (HXR) sources located in the corona was recently found, which implies that the collisionally thick target model (CTTM) applies even to the corona. We investigated whether this idea can be independently verified by microwave radiations which have been known as the best companion to HXRs. This study is conducted on the GOES M2.3 class flare which occurred on 2002 September 9 and was observed by the Reuven Ramaty High-Energy Solar Spectroscopic Imager and the Owens Valley Solar Array. Interpreting the observed energy-dependent variation of HXR source size under the CTTM, the coronal density should be as high as 5 Multiplication-Sign 10{sup 11} cm{sup -3} over a distance of up to 12''. To explain the cutoff feature of the microwave spectrum at 3 GHz, however, we require a density no higher than 1 Multiplication-Sign 10{sup 11} cm{sup -3}. Additional constraints must be placed on the temperature and magnetic field of the coronal source in order to reproduce the microwave spectrum as a whole. First, a spectral feature called the Razin suppression requires a magnetic field in a range of 250-350 G along with high viewing angles around 75 Degree-Sign . Second, to avoid excess fluxesmore » at high frequencies due to the free-free emission that was not observed, we need a high temperature {>=}2 Multiplication-Sign 10{sup 7} K. These two microwave spectral features, Razin suppression and free-free emissions, become more significant at regions of high thermal plasma density and are essential for validating and determining additional parameters of the coronal HXR sources.« less
35634571
Expression of Interest and RD Proposal for the Study of Nucleon Decay and Neutrino Physics Using a Large Underground Water Cherenkov Detector: UNO
209866467
CP violation in the Cabibbo suppressed decay tau ---> K pi tau-neutrino with polarized tau leptons
25175
New precision limit on the strange vector form factors of the proton.
The parity-violating cross-section asymmetry in the elastic scattering of polarized electrons from unpolarized protons has been measured at a four-momentum transfer squared Q2 = 0.624  GeV2 and beam energy E(b) = 3.48  GeV to be A(PV) = -23.80 ± 0.78(stat) ± 0.36(syst) parts per million. This result is consistent with zero contribution of strange quarks to the combination of electric and magnetic form factors G(E)(s) + 0.517G(M)(s) = 0.003 ± 0.010(stat) ± 0.004(syst) ± 0.009(ff), where the third error is due to the limits of precision on the electromagnetic form factors and radiative corrections. With this measurement, the world data on strange contributions to nucleon form factors are seen to be consistent with zero and not more than a few percent of the proton form factors.