122977256
Large pT J/psi production in double pomeron exchange processes
Presented here is a study of the large pT J/ production in double pomeron exchange processes via gluon fragmentation at hadron colliders. We use three sets of parametrization (hard gluon, hard quark, and soft gluon) for the parton distribution in the pomeron to estimate the production cross section. We find that the J/ production rate is sensitive to the gluon component of the pomeron. Especially, at the LHC the soft gluon parametrization gives the J/ production rate two order of magnitude larger than that hard gluon parametrization gives.
16473915
D-wave charmonium production in B decays
The calculation of D-wave charmonium production rates in B meson decays under the NRQCD factorization formalism is presented. We find that the inclusion of the color-octet contributions permits us to detect the D-wave charmonium states in B decays at present experimental facilities. The same amount of signals of the 2{sup {minus}{minus}} D-wave state as that of {psi}{sup {prime}} could be observed at CERN LEP and CESR. We also predict that the relative production rates for four D-wave states are {delta}{sup c}:{delta}{sub 1}{sup c}:{delta}{sub 2}{sup c}:{delta}{sub 3}{sup c}=2.5:3:5:7, where {delta}{sup c}, {delta}{sub 1}{sup c}, {delta}{sub 2}{sup c}, {delta}{sub 3}{sup c} represent, respectively, the 2{sup {minus}+}, 1{sup {minus}{minus}}, 2{sup {minus}{minus}}, 3{sup {minus}{minus}} states. {copyright} {ital 1997} {ital The American Physical Society}
36678859
Semi-inclusive DIS: Factorization
Semi-inclusive DIS: Factorization Feng Yuan 1,2 1- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA 2- RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973, USA In this talk, we will present a QCD factorization theorem for the semi-inclusive deep- inelastic scattering with hadrons in the current fragmentation region detected at low transverse momentum. There has been considerable experimental and theoretical interest in semi-inclusive hadron production in deep inelastic scattering (SIDIS) processes. For example, by studying the polarized and unpolarized SIDIS, one will be able to identify the sea quark distribution and polarization in nucleon, and the experimental results from the HERMES collabora- tion have revealed nontrivial sea structure in nucleon [1]. More recently, SIDIS opened a new window to study the transverse momentum dependent (TMD) parton distributions and fragmentation functions from the low transverse momentum hadron production. The trans- verse momentum distribution of the ﬁnal state hadron is directly related to the transverse momentum dependence of the parton distributions and fragmentation. These studies will provide new opportunities to explore the partonic structure of nucleon, especially the three- dimension distribution of partons inside nucleon. The DIS experiments, including HERMES, COMPAS, and JLab Hall B collaborations, have studied various azimuthal asymmetries in SIDIS. In particular, the HERMES collaboration found sizable single spin asymmetries in these processes involving nontrivial QCD eﬀects and hadron structure. On the theory side, there has been great progress in the last few years too. In this short talk, it is impossible to cover all these important physics. Rather, I would like to focus on one of the questions concerning applying the QCD to the description of the semi-inclusive DIS, in particular, the QCD factorization for SIDIS. Unlike the inclusive DIS process, SIDIS is more involved because of additional hadron measurement in the ﬁnal state. We can classify the SIDIS processes into three diﬀerent categories. First, if we integrate out the transverse momentum of the ﬁnal state hadron, these SIDIS will be similar to the inclusive DIS, and a collinear factorization is applicable. The cross section can be written as a convolution of the integrated parton distribution and fragmentation function and the hard partonic cross section which can be calculated from perturbative QCD. Second class is the large trans- verse momentum SIDIS. When transverse momentum is large enough (in order of Q, the virtuality of the virtual photon), again a collinear factorization shall be used to analyze the cross section. The third class is the low transverse momentum hadron production, where a collinear factorization approach may not be applicable because the transverse momentum of the ﬁnal state hadron is small compared to the hard scale Q. In order to describe this class of processes, we have to introduce a new factorization theorem, involving the transverse momentum dependent parton distribution and fragmentation functions. Rigorous theoret- ical studies in this direction started from the classical work on semi-inclusive processes in e + e − annihilation by Collins and Soper [2], where a QCD factorization was proved, and ∗ This work was supported in part by the U.S. Department of Energy under contract DE-AC02- 05CH11231. We are grateful to RIKEN, Brookhaven National Laboratory and the U.S. Department of Energy (contract number DE-AC02-98CH10886) for providing the facilities essential for the completion of this work. DIS 2008
211730981
Transverse Momentum Dependent Parton Distri- butions at an Electron-Ion Collider
Transverse momentum dependent (TMD) parton distributions have attracted great attentions from both experiment and theory sides in recent years [1]. They open a new window to investigate the strong interaction physics and the fundamental properties of QCD theory. At the leading order, there are eight independent TMD quark distributions: three k⊥-even distributions (unpolarized, longitudinal polarized quark distributions, and the quark transversity), and five k⊥-odd distributions. Because of the correlations between the quark transverse momentum and the nucleon spin, the TMDs naturally provide important information on the dynamics of partons in the transverse plane in momentum space. Measurements of the k⊥-odd quark distributions provide information about the correlation between the quark orbital angular momentum and the nucleon/quark spin because they require wave function components with nonzero orbital angular momentum. One particular example is the quark Sivers function f 1T which describes the transverse momentum distribution correlated with the transverse polarization vector of the nucleon. There have been strong evidence of the Sivers effect in the DIS experiments observed by the HERMES, COMPASS, and JLab Hall A collaborations [2, 3, 4] (see Fig. 1). An important aspect of the Sivers functions which has been revealed theoretically in last few years is the process dependence and the color gauge invariance [5, 6]. Together with the Boer-Mulders function, they are denoted as naive time-reversal odd (T-odd) functions. In the semi-inclusive DIS (SIDIS), where a leading hadron is detected in coincidence with the scattered lepton, the quark Sivers function arises due to the exchange of (infinitely many) gluons between the active struck quark and the remnants of the target, which is referred as the final state interaction effects in DIS. On the other hand, for the Drell-Yan lepton pair production process, it is the initial state interaction effects. As a consequence, the quark Sivers functions differ by a sign in these two processes. This nonuniversality is a fundamental prediction from the gauge invariance of QCD [6]. The experimental check of this sign change is currently one of the outstanding topics in hadronic physics, and Sivers functions from Drell-Yan process can be measured at RHIC. In high energy hadronic processes where we hope to study the transverse momentum dependent parton distributions, besides the transverse momentum, an additional hard momentum scale is essential to make the proper use of the TMD parton distributions and fragmentation functions. This hard momentum scale needs to be much larger than the transverse momentum scale. At the electron-ion collider, DIS processes naturally provide a hard momentum scale: Q, the virtuality for the virtual photon. More importantly, the EIC design has a wide range
118378485
Phases of Augmented Hadronic Light-Front Wave Functions
It is an important question whether the final/initial state gluonic interactions which lead to naive-time-reversal-odd single-spin asymmetries and diffraction at leading twist can be associated in a definite way with the light-front wave function hadronic eigensolutions of QCD. We use light-front time-ordered perturbation theory to obtain augmented light-front wave functions which contain an imaginary phase which depends on the choice of advanced or retarded boundary condition for the gauge potential in light-cone gauge. We apply this formalism to the wave functions of the valence Fock states of nucleons and pions, and show how this illuminates the factorization properties of naive-time-reversal-odd transverse momentum dependent observables which arise from rescattering. In particular, one calculates the identical leading-twist Sivers function from the overlap of augmented light-front wavefunctions that one obtains from explicit calculations of the single-spin asymmetry in semi-inclusive deep inelastic lepton-polarized nucleon scattering where the required phases come from the final-state rescattering of the struck quark with the nucleon spectators.
54724455
Theoretical Overview on Recent Developments in Transverse Spin Physics
Transverse-spin physics has been very active and rapidly developing in the last few years. In this talk, I will briefly summarize recent theoretical developments, focusing on the associated QCD dynamics in transverse spin physics.
119100083
A modified variational principle for gravity in the modified Weyl geometry
The usual interpretation of the Weyl geometry is modified in two senses. First, both the additive Weyl connection and its variation are treated as (1, 2) tensors under the action of the Weyl covariant derivative. Second, a modified covariant derivative operator is introduced which still preserves the tensor structure of the theory. With its help, the Riemann tensor in the Weyl geometry can be written in a more compact form. We justify this modification in detail from several aspects and obtain some insights along the way. By introducing some new transformation rules for the variation of tensors under the action of the Weyl covariant derivative, we find a Weyl version of the Palatini identity for the Riemann tensor. To derive the energy–momentum tensor and equations of motion for gravity in the Weyl geometry, one naturally applies this identity at first, and then converts the variation of the additive Weyl connection to those of the metric tensor and Weyl gauge field. We also discuss possible connections to the current literature on the Weyl-invariant extension of massive gravity and the variational principles in f(R) gravity.
123414742
General Rotating Black Hole with Four Charges and Liouville Theory
By considering the dual Liouville theory emerging in the near-horizon limit, we study the thermodynamics of general rotating black hole with four charges in four dimensions. Both the black hole entropy and temperature are found to agree with the gravitational expectations. The relations between the new Liouville formalism and the anomaly approach are also discussed.
118374860
Real-time Detection and Rapid Multiwavelength Follow-up Observations of a Highly Subluminous Type II-P Supernova from the Palomar Transient Factory Survey
The Palomar Transient Factory (PTF) is an optical wide-field variability survey carried out using a camera with a 7.8 deg^2 field of view mounted on the 48 inch Oschin Schmidt telescope at Palomar Observatory. One of the key goals of this survey is to conduct high-cadence monitoring of the sky in order to detect optical transient sources shortly after they occur. Here, we describe the real-time capabilities of the PTF and our related rapid multiwavelength follow-up programs, extending from the radio to the γ-ray bands. We present as a case study observations of the optical transient PTF10vdl (SN 2010id), revealed to be a very young core-collapse (Type II-P) supernova having a remarkably low luminosity. Our results demonstrate that the PTF now provides for optical transients the real-time discovery and rapid-response follow-up capabilities previously reserved only for high-energy transients like gamma-ray bursts.
118654021
Thermodynamics of nonspherical black holes from Liouville theory
A Liouville formalism was proposed many years ago to account for the black hole entropy. It was recently updated to connect thermodynamics of general black holes, in particular the Hawking temperature, to two-dimensional Liouville theory. This relies on the dimensional reduction to two-dimensional black hole metric. The relevant dilaton gravity model can be rewritten as a Liouville-like theory. We refine the method and give general formulas for the corresponding scalar and energy–momentum tensors in Liouville theory. This enables us to read off the black hole temperature using a relation which was found about three decades ago. Then the range of application is extended to include nonspherical black holes such as neutral and charged black rings, topological black hole and the case coupled to a scalar field. As for the entropy, following previous authors, we invoke the Lagrangian approach to central charge by Cadoni and then use the Cardy formula. The general relevant parameters are also given. This approach is more advantageous than the usual Hamiltonian approach which was used by the old Liouville formalism for black hole entropy.
118602952
Hidden conformal symmetry of extremal Kaluza-Klein black hole in four dimensions
We study the hidden conformal symmetry of four-dimensional extremal Kaluza-Klein black hole. The scalar Laplacian corresponding to the radial equation in the near-region is rewritten in terms of the $ {\text{SL}}\left( {2,\mathbb{R}} \right) $ quadratic Casimir. Using the first law of black hole thermodynamics, this symmetry enables us to obtain the conjugate charges for the CFT side. The real-time correlators are also found to agree with the CFT expectations.