7040957
Coherent multiple scattering effect in DIS
We present a QCD calculation of the coherent multiple scattering effect on single hadron production in semi-inclusive lepton-nucleus deep inelastic scattering (DIS). We show that the destructive interference of coherent multiple scattering leads to suppression in hadron productions. The suppression is similar to the expectations of energy loss calculations. We compare our calculation with experimental data.
118914273
Direct photon production in a nuclear environment
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.
42222465
Universality in the nuclear dependence coefficient alpha(q(T))
We derive the nuclear dependence coefficient alpha(q(T)) for Drell-Yan and J/psi production. We show that at small q(T), alpha(q(T)) is given by a universal functional form: alpha(q(T)) = a+bq(2)(T), and the parameters a and b are completely determined by either perturbatively calculable or independently measurable quantities. This universal functional form alpha(q(T)) is insensitive to A, and is consistent with existing data.
13900650
Nuclear dependence in the Drell-Yan transverse momentum distribution
We calculate the nuclear enhancement in the Drell-Yan transverse momentum distribution in hadron-nucleus collisions. In terms of the multiple scattering picture, we compute the contributions from double scattering. Applying the generalized factorization theorem, we express the nuclear enhancement in terms of twist-4 nuclear parton correlation functions. Using the known information on these twist-4 parton correlation functions, we estimate the nuclear enhancement for Drell-Yan pairs in the large q{sub T} region. We also discuss the source of nuclear suppression in the small q{sub T} region. {copyright} {ital 1998} {ital The American Physical Society}
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}
16156190
Dissipative potential induced by QCD at finite temperature and density
In the framework of QCD at finite temperature, we have obtained dissipative factors for the effective potential between q and {bar q} which would partly explain the J/{psi} suppression in the quark gluon plasma (QGP). The derivation of the dissipative potential in the QGP is presented and the case in the hadron matter (HM) is briefly discussed. The suppression effects are numerically estimated based on simple approximations and a comparison with that caused by the Debye screening mechanism is also presented. {copyright} {ital 1997} {ital The American Physical Society}
124384514
Intermediate Range Force Contributions to Dynamical Chiral Symmetry Breaking in QCD
We propoee the intermediate range QCD force singular like by analysing the gluon propagator in the nonperturbative region from QCD sum rules. With the help of the Slavnov-Taylor-Ward identity we derive the equations for the nonperturbative quark propagator from the Schwinger-Dyson (SD) equation. Solutions for the quark propagator in two special cases are given. We find that the intermediate range force is also responsible for the chiral symmetry breaking in QCD.
119547297
TEST ON APPLICATION RANGE OF QCD SUM-RULES FROM BARYON SPECTROSCOPY
By considering the nonperturbative QCD effect via quark and gluon condensates, the confinement terms in effective q-q potential can automatically be given. A potential in the form of (Yukawa-type terms) where positive and negative signs appear alternatively in 's is proposed. To testify the validity range of QCD sum rules, the experimental baryon spectrum is fitted and the values of 's as well as their signs are obtained. It is found that in the baryon spectrum calculation, the terms of and are important and higher terms beyond can be neglected. Comparing these values with the result calculated from QCD sum rules, some agreements and disagreements are found.
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.
117975255
QCD factorization for $\Lambda_b^0\to\Lambda_c^+\pi^-$
We prove that in the limit $m_b, m_c\to\infty$ with $m_c/m_b$ fixed, factorization holds at order $\alpha_s$ for the decay $\Lambda_b^0\to\Lambda_c^+\pi^-$. This proof is done in the infinite-momentum frame in which the momenta of $\pi$, $\Lambda_c$, and $\Lambda_b$ go to infinity. Our result is renormalization scale and scheme independent at $\mathcal{O}(\alpha_s)$. This is the same as QCD factorization for $B \to D \pi$.