17743185
Nuclear dependence in transverse momentum distribution for Drell-Yan pair
Abstract In terms of multiple scattering picture, I compute the nuclear dependence in Drell-Yan transverse momentum distribution, dσ / dQ 2 dq T 2 , in hadron-nucleus collisions. I present the results for large q T region and discuss the possible suppression in small q T region.
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.
16223404
Gluon minijet production in nuclear collisions at high energies
We show explicitly that the leading soft gluon p{sub T} distribution, predicted by Kovner, McLerran, and Weigert after solving classical Yang-Mills equations, can be understood in terms of conventional QCD perturbation theory. We also demonstrate that the key logarithm in their result represents the logarithm in DGLAP evolution equations. {copyright} {ital 1999} {ital The American Physical Society}
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
118914273
Direct photon production in a nuclear environment
29148516
Multiple parton scattering in nuclei: Parton energy loss
Abstract Multiple parton scattering and induced parton energy loss are studied in deeply inelastic scattering (DIS) off nuclei. The effect of multiple scattering of a highly off-shell quark and the induced parton energy loss is expressed in terms of the modification to the quark fragmentation functions. We derive such modified quark fragmentation functions and their QCD evolution equations in DIS using the generalized factorization of higher twist parton distributions. We consider double-hard and hard-soft parton scattering as well as their interferences in the same framework. The final result, which depends on both the diagonal and off-diagonal twist-four parton distributions in nuclei, demonstrates clearly the Landau–Pomeranchuk–Migdal interference features and predicts a unique nuclear modification of the quark fragmentation functions.
15904299
Chiral Extrapolation of Lattice Data for Heavy Meson Hyperfine Splittings
Abstract.We investigate the chiral extrapolation of the lattice data for the light-heavy meson hyperfine splittings D*-D and B*-B to the physical region for the light quark mass. The chiral loop corrections providing a non-analytic behavior in mπ are consistent with the chiral perturbation theory for heavy mesons. Since chiral loop corrections tend to decrease the already too low splittings obtained from linear extrapolation, we investigate two models to guide the form of the analytic background behavior: the constituent quark potential model, and the covariant model of QCD based on the ladder-rainbow truncation of the Dyson-Schwinger equations. The extrapolated hyperfine splittings remain clearly below the experimental values even allowing for the model dependence in the description of the analytic background.
17365172
Heavy quark distribution functions in heavy baryons
Using the Bethe-Salpeter (B-S) equations for heavy baryons Lambda_Q, Sigma_Q, Xi_Q and Omega_Q (Q=b or c), which were established in previous work, we calculate the heavy quark distribution functions in these baryons. The numerical results indicate that these distribution functions have an obvious peak at some fraction, alpha_0, of the baryon's light-cone ``plus'' momentum component carried by the heavy quark, and that as m_Q becomes heavier this peak becomes sharper and closer to 1. The dependence of the distribution functions on various input parameters in the B-S model is also discussed. The results are seen to be qualitatively similar to an existing phenomenological model.
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%.
119299313
CP violation in $B^{\pm} \rightarrow \pi^{\pm}\pi^{+}\pi^{-}$ in the region with low invariant mass of one $\pi^{+}\pi^{-}$ pair
Recently, the large CP asymmetries in B → πππ decays were found by the LHCb Collaboration to localize in the region m π+π− < 0.4 GeV. We find such large localized CP asymmetries may be due to the interference between a light scalar and ρ(770) intermediate resonances. Consequently, we argue that the distribution of CP asymmetries in the Dalitz plots of three-body B decays could be very helpful for identifying the presence of the scalar resonance.
123537561
DK molecule in the Bethe-Salpeter equation approach in the heavy quark limit
In the heavy quark limit, we establish the Bethe-Salpeter equation for the possible molecular state containing one heavy meson D and one light meson K. With the kernel induced by one-particle-exchange diagrams, we solve the Bethe-Salpeter equation numerically in the ladder and covariant instantaneous approximations and find that the DK bound state may exist. Assuming the observed state D*(s0)(2317)(+) is an S-wave DK molecular bound state we calculate the strong decay width of D*(s0)(2317)(+). Our prediction for the decay width Gamma(D*(s0)(2317)(+) -> D-s(+) pi(0)) is consistent with the previous investigations and the current experimental data.