62889681
Azimuthal asymmetries in semi-inclusive DIS with polarized beam and/or target and their nuclear dependences
Using the formalism obtained from collinear expansion, we calculate the differential cross section and azimuthal asymmetries in semi-inclusive deeply inelastic lepton-nucleon (nucleus) scattering process e − +N(A) → e − +q+X with both polarized beam and polarized target up to twist-3. We derive the azimuthal asymmetries in terms of twist-3 parton correlation functions. We simplify the results by using the QCD equation of motion that leads to a set of relationships between different twist-3 functions. We further study the nuclear dependence of azimuthal asymmetries and show that they have similar suppression factors as those in the unpolarized reactions.
122962983
Higher Twist Contributions to the Azimuthal Asymmetries in SIDIS
This is intended to be a summary of a series of publications [1, 2, 3] carried out by our group. We showed that collinear expansion can be extended to the semi-inclusive deep inelastic scattering process e + p → e + q + X as a systematic way of studying higher twist effects. We calculated the cross section up to twist-3 level for different polarized and unpolarized cases, and obtained the azimuthal asymmetry cos in terms of gauge invariant twist-3 TMD parton correlation functions [1]. We further calculated the complete cross section up to twist-4 level for the unpolarized case, and obtained the azimuthal asymmetry cos 2 expressed in terms of gauge invariant twist-4 TMD parton correlation functions [3]. We also showed that the nuclear dependence of the TMD distributions can be obtained from the gauge link and studied the nuclear dependence of both cos and cos 2 asymmetries with a Gaussian ansatz for transverse momentum dependence of parton correlation functions [2, 3].
119164342
Negative off-diagonal conductivities in a weakly coupled quark-gluon plasma at the leading-log order
We calculate the conductivity matrix of a weakly coupled quark-gluon plasma at the leading-log order. By setting all quark chemical potentials to be identical, the diagonal conductivities become degenerate and positive, while the off-diagonal ones become degenerate but negative (or zero when the chemical potential vanishes). This means a potential gradient of a certain fermion flavor can drive backward currents of other flavors. A simple explanation is provided for this seemingly counter intuitive phenomenon. It is speculated that this phenomenon is generic and most easily measured in cold atom experiments.
119215813
Symmetry violations in few-body reactions: old and new approaches
Abstract As an attempt to find a way to resolve the discrepancy between calculated by traditional methods PV e_ects and the available set of experimental data, we analyze the methods of calculations of symmetry violating e_ects in fewbody nuclear systems. The overview of methods of calculations of PV and TRIV e_ects in few-body neutron induced reactions is presented with the analysis of values of calculated parameters and their accuracy.
36350052
Time reversal invariance violation in neutron-deuteron scattering
Time reversal invariance-violating (TRIV) effects in low-energy elastic neutron-deuteron scattering are calculated using meson exchange and EFT-type TRIV potentials in a distorted-wave Born approximation with realistic hadronic strong interaction wave functions, obtained by solving the three-body Faddeev equations in configuration space. The relation between TRIV and parity-violating observables is discussed.
18094401
Solar-neutrino reactions on deuteron in effective field theory
Abstract The cross sections for low-energy neutrino–deuteron reactions are calculated within heavy-baryon chiral perturbation theory employing a cut-off regularization scheme. The transition operators are derived up to next-to-next-to-next-to-leading order in the Weinberg counting rules, while the nuclear matrix elements are evaluated using the wave functions generated by a high-quality phenomenological NN potential. With the adoption of the axial-current-four-nucleon coupling constant fixed from the tritium beta decay data, our calculation is free from unknown low-energy constants. Our results exhibit a high degree of stability against different choices of the cutoff parameter, a feature which indicates that, apart from radiative corrections, the uncertainties in the calculated cross sections are less than 1%.
32868444
Parity violation in low-energy neutron-deuteron scattering
Parity violating effects for low energy elastic neutron deuteron scattering are calculated for DDH and EFT-type of weak potentials in a Distorted Wave Born Approximation, using realistic hadronic strong interaction wave functions, obtained by solving three-body Faddeev equations in configuration space. The results of relation between physical observables and low energy constants can be used to fix low energy constants from experiments. Potential model dependencies of parity violating effects are discussed.
119028691
In-medium modification of P-wave charmonia from QCD sum rules
We investigate the changes of the masses and widths of {chi}{sub c0} and {chi}{sub c1} in hot gluonic matter near T{sub c} and in a nuclear medium using QCD sum rules. As in the previous works for the J/{psi} and {eta}{sub c}, in-medium effects are incorporated through the changes of gluon condensates. Twist-2 terms for the {sup 3}P{sub 0}({chi}{sub c0}) and {sup 3}P{sub 1}({chi}{sub c1}) are also included for the first time. The results show that larger mass shifts and width broadenings take place as compared to the S-wave states. As the critical change take place near T{sub c}, related measurements can reveal critical phenomenon in QCD.