117590086
CHARMONIUM POLARIZATION AT THE TEVATRON
The current issues on the polarization of prompt J/ψ at the Tevatron is discussed. The prediction based on the nonrelativistic QCD factorization approach agrees with measurements from the CDF collaboration at intermediate values of pT, but disagrees at the large values of pT measured.
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.
125995563
Double quarkonium production at the LHC
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.
17297484
Color-octet mechanism in the inclusive D-wave charmonium productions in B decays
The inclusive D-wave charmonium production rates in B decays are considered in the Bodwin-Braaten-Lepage (BBL) approach. We find that the color-octet subprocesses B → cc(3S1(8) or 3PJ(80) + s, d, followed by the transition cc(3S1(8), or 3PJ(8)) → 3DJ, strongly dominate over any other subprocess, due to the large Wilson coefficient for the ΔB = 1 effective lagrangian. Assuming that the numerical values of the matrix elements 〈0|O3DJ(3S1(8))|0〉 and 〈0|O3DJ(3PJ(8))|0〉 are the same order of magnitudes with the 〈0|Oψ′ (3S1(8))|0〉, we find that the 1,3D2 can be observed B-factories.
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.
54998219
Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
A search for the Standard Model Higgs boson in proton–proton collisions with the ATLAS detector at the LHC is presented. The datasets used correspond to integrated luminosities of approximately 4.8 fb−1 collected at View the MathML source in 2011 and 5.8 fb−1 at View the MathML source in 2012. Individual searches in the channels H→ZZ(⁎)→4l, H→γγ and H→WW(⁎)→eνμν in the 8 TeV data are combined with previously published results of searches for H→ZZ(⁎), WW(⁎), View the MathML source and τ+τ− in the 7 TeV data and results from improved analyses of the H→ZZ(⁎)→4l and H→γγ channels in the 7 TeV data. Clear evidence for the production of a neutral boson with a measured mass of View the MathML source is presented. This observation, which has a significance of 5.9 standard deviations, corresponding to a background fluctuation probability of 1.7×10−9, is compatible with the production and decay of the Standard Model Higgs boson.
119110867
The Variation of Relative Magnetic Helicity around Major Flares
We have investigated the variation of magnetic helicity over a span of several days around the times of 11 X-class flares which occurred in seven active regions (NOAA 9672, 10030, 10314, 10486, 10564, 10696, and 10720) using the magnetograms taken by the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory (SOHO). As a major result we found that each of these major flares was preceded by a significant helicity accumulation, (1.8–16) × 1042 Mx2 over a long period (0.5 to a few days). Another finding is that the helicity accumulates at a nearly constant rate, (4.5–48) × 1040 Mx2 hr−1, and then becomes nearly constant before the flares. This led us to distinguish the helicity variation into two phases: a phase of monotonically increasing helicity and the following phase of relatively constant helicity. As expected, the amount of helicity accumulated shows a modest correlation with time-integrated soft X-ray flux during flares. However, the average helicity change rate in the first phase shows even stronger correlation with the time-integrated soft X-ray flux. We discuss the physical implications of this result and the possibility that this characteristic helicity variation pattern can be used as an early warning sign for solar eruptions.
118567194
The Light and Period Variations of the Eclipsing Binary AA Ursae Majoris
We present new multiband CCD photometry for AA UMa made on eight nights between 2009 January and March; the R light curves are the first ever compiled. Historical light curves, as well as ours, display partial eclipses and inverse O'Connell effects, with Max I fainter than Max II. Among possible spot models, a cool spot on either of the component stars and its variability with time permit good light-curve representations for the system. A total of 194 eclipse timings over 81 yr, including our five timings, were used for ephemeris computations. We found that the orbital period of the system has varied due to a periodic oscillation overlaid on an upward parabolic variation. The continuous period increase at a fractional rate of +1.3 × 10-10 is consistent with that calculated from the Wilson & Devinney code and can be interpreted as a thermal mass transfer from the less massive to the more massive secondary star at a rate of 6.6 × 10-8 M⊙ yr-1. The periodic component is in satisfactory accord with a light-time effect due to an unseen companion with a period of 28.2 yr, a semiamplitude of 0.007 days, and a minimum mass of M3 sin i3 = 0.25 M⊙, but this period variation could also arise from magnetic activity.
53421865
Maximal electric dipole moments of nuclei with enhanced Schiff moments
The electric dipole moments (EDMs) of heavy nuclei, such as 199Hg, 225Ra and 211Rn, can be enhanced by the Schiff moments induced by the presence of nearby parity-doublet states. Working within the framework of the maximally CP-violating and minimally flavour-violating (MCPMFV) version of the MSSM, we discuss the maximal values that such EDMs might attain, given the existing experimental constraints on the Thallium, neutron and Mercury EDMs. The maximal EDM values of the heavy nuclei are obtained with the help of a differential-geometrical approach proposed recently that enables the maxima of new CP-violating observables to be calculated exactly in the linear approximation. In the case of 225Ra, we find that its EDM may be as large as 6 to 50 × 10−27e ∙ cm.
119122873
Longitudinal top polarization as a probe of a possible origin of forward–backward asymmetry of the top quark at the Tevatron
Abstract If the forward–backward (FB) asymmetry of top quark ( A FB ) observed at the Tevatron deviates from the SM prediction, there must be P -violating interactions in q q ¯ → t t ¯ . This new interaction will necessarily affect the top spin polarization. In this Letter, we perform a model independent analysis on the longitudinal (anti)top polarization ( P L and P ¯ L ) using an effective lagrangian with dim-6 four-quark operators relevant for q q ¯ → t t ¯ , and show that the P -odd observable corresponding to the polarization difference ( P L − P ¯ L ) gives important informations on the chiral structures of new physics that might be relevant to the A FB .