120908811
Mass spectra of doubly heavy mesons in Regge phenomenology
In Regge phenomenology, we first study the spectra of charmonium and bottomonium in the (n, M-2) plane and predict masses of some charmonium and bottomonium states which have not been observed now. Then, with the aid of the additivity of intercepts and inverse slopes, we calculate the masses of ground S-wave and P-wave c (b) over bar meson states and their first radial excited states. The predictions are in reasonable agreement with the existing experimental data and those suggested in many other approaches. The predictions may be useful for the discovery of the unobserved c (c) over bar, b (b) over bar, c (b) over bar mesons and the J(P) assignment of these states.
118695285
Detection of supernova neutrinos on the Earth for large theta13
Supernova (SN) neutrinos detected on the Earth are subject to the shock wave effects, the Mikheyev-Smirnov-Wolfenstein (MSW) effects, the neutrino collective effects and the Earth matter effects. Considering the recent experimental result about the large mixing angle θ13 (⋍ 8.8 ) provided by the Daya Bay Collaboration and applying the available knowledge for the neutrino conversion probability in the high resonance of SN, PH , which is in the form of hypergeometric function in the case of large θ13, we deduce the expression of PH taking into account the shock wave effects. It is found that PH is not zero in a certain range of time due to the shock wave effects. After considering all the four physical effects and scanning relevant parameters, we calculate the event numbers of SN neutrinos detected at the Daya Bay experiment. From the numerical results, it is found that the behaviors of neutrino event numbers detected on the Earth depend on the neutrino mass hierarchy and neutrino spectrum parameters including the temperature Tα, the dimensionless pinching parameter ηα or βα (where α refers to neutrino flavor), the average energy 〈Eα〉, and the SN neutrino luminosities Lα. We also compare the results of two parametrization methods for the neutrino energy distributions and give the ranges of SN neutrino event numbers that will be detected at the Daya Bay experiment.
119271994
$CP$ violation for $B^{0}\rightarrow \rho^{0}(\omega)\rho^{0}(\omega) \rightarrow \pi^+\pi^-\pi^+\pi^-$ in QCD factorization
In the QCD factorization (QCDF) approach we study the direct $CP$ violation in $\bar{B}^{0}\rightarrow\rho^0(\omega)\rho^0(\omega)\rightarrow\pi^+\pi^-\pi^+\pi^-$ via the $\rho-\omega$ mixing mechanism. We find that the $CP$ violation can be enhanced by double $\rho-\omega$ mixing when the masses of the $\pi^+\pi^-$ pairs are in the vicinity of the $\omega$ resonance, and the maximum $CP$ violation can reach 28{\%}. We also compare the results from the naive factorization and the QCD factorization.
1562870
Weak semileptonic decays of heavy baryons containing two heavy quarks
In the heavy quark limit a heavy baryon which contains two heavy quarks is believed to be composed of a heavy diquark and a light quark. Based on this picture, we evaluate the weak semileptonic decay rates of such baryons. The transition form factors between two heavy baryons are associated with those between two heavy mesons by applying superflavor symmetry. The effective vertices of the W boson and two heavy diquarks are obtained in terms of the Bethe-Salpeter equation. Numerical predictions on these semileptonic decay widths are presented and they will be tested in future experiments. [S0556-2821(98)00721-8].
119535783
A dynamical mechanism for the hairpin diagram
SummaryBased on the nonvalence quark-antiquark and gluon constituent structure of mesons we give a reasonable dynamical mechanism which can induce the hairpin diagram without violating the well-observed OZI rule. We calculate the hairpin amplitudes of
$$D^0 \to \overline K ^0 \eta $$
 and
$$\overline K ^0 \eta '$$
 normalized by
$$D^0 \to \overline K ^0 \pi ^0 $$
 and have found that the hairpin diagram can give rise to substantial contributions to the decays where a meson with aSU(3) flavor singlet component is involved in the final state. In this scenario, we also obtain the branching ratio of
$$D^0 \to \overline K ^0 \phi $$
 as 0.55% in comparison with the experimental data of 0.83%.
13937852
Strong decays of heavy baryons in the Bethe-Salpeter formalism
In this paper we study the properties of diquarks (composed of u and/or d quarks) in the Bethe-Salpeter (BS) formalism under the covariant instantaneous approximation. We calculate their BS wave functions and study their effective interaction with the pion. Using the effective coupling constant among the diquarks and the pion, in the heavy quark limit m{sub Q}{yields}{infinity}, we calculate the decay widths of {sigma}{sub Q}{sup (*)} (Q=c, b) in the BS formalism under the covariant instantaneous approximation and then give predictions of the decay widths {gamma}({sigma}{sub b}{sup (*)}{yields}{lambda}{sub b}+{pi})
17569178
Nuclear enhanced power corrections to DIS structure functions
Abstract We calculate nuclear enhanced power corrections to structure functions measured in deeply inelastic lepton–nucleus scattering in Quantum Chromodynamics (QCD). We find that the nuclear medium enhanced power corrections at order of O ( α s / Q 2 ) enhance the longitudinal structure function  F L , and suppress the transverse structure function  F 1 . We demonstrate that strong nuclear effects in σ A / σ D and R A / R D , recently observed by HERMES Collaboration, can be explained in terms of the nuclear enhanced power corrections.
118914273
Direct photon production in a nuclear environment
14220177
Leading Soft Gluon Production in High Energy Nuclear Collisions
The leading soft gluon pT distribution in heavy ion collisions was ob-tained by Kovner, McLerran, and Weigert after solving classical Yang-Mills equations. I show explicitly this result can be understood in terms of conventional QCD perturbation theory. I also demonstrate that the key logarithm in their result represents the logarithm in DGLAP evolution equations.
15964205
Probing Multiparton Correlation Functions In Deeply Inelastic Scattering
We derive the transverse momentum broadening of the leading pions in deeply inelastic lepton-nucleus collisions. We argue that the measurement of such transverse momentum broadening can provide direct information on the multiple-parton correlation functions inside a nucleus. We also estimate the numerical values of such broadening at different values of xB and Q 2. 11.80.La, 12.38.Bx, 13.85.Ni, 24.80.-x Typeset using REVTEX
118936305
Multiple scattering and energy loss in semi-inclusive deeply inelastic eA scattering
We calculate the multiple scattering effect on single hadron production in semi-inclusive lepton-nucleus deeply inelastic scattering. We show that the quantum interference of multiple scattering amplitudes leads to suppression in hadron productions. At the leading power in medium length, the suppression can be approximately expressed in terms of a shift in $z$ of the fragmentation function $D(z)$, and could be therefore interpreted as the collisional energy loss. We compare our calculation with existing experimental data. We also discuss the effect of quark mass on the suppression. Our approach can be extended to other observables in hadronic collisions.