119246377
Single spin asymmetries in heavy quark and antiquark productions
Abstract The single transverse spin asymmetries in heavy quark and antiquark production from the quark–antiquark annihilation channel contribution is studied by taking into account the initial and final state interactions effects. Because of the different color charges, the final state interaction effects lead to about a factor of 3 difference in the spin asymmetry for heavy quark over that for the antiquark in the valence region of low energy pp collisions. The experimental study of this model-independent prediction shall provide a crucial test for the underlying mechanism for the single spin asymmetry phenomena.
117586880
Prompt $J/\psi$ production at $e^{+} e^{-}$ colliders
In this paper, we discuss the prompt j/psi production at e^+e^- colliders via color-singlet and color-octet production mechanisms. The color-singlet production processes include 1) e^+e^- to J/\psi gg; 2) e^+e^- to J/\psi c\bar{c}; 3) e^+e^- to q \bar q ggJ/\psi and e^+e^- to q \bar q g\chi_c followed by \chi_c to J/\psi \gamma. The color-octet production processes include 1) e^+e^- to J/\psi g; 2) e^+e^- to j/psi q\bar q. Of all these production channels, we find that the color-octet contributions dominate over the color-singlet contributions at any energy scales. At low energies (\sqrt{s}< 20 GeV), the dominant channel is e^+e^- to J/\psi g whereas at high energies e+e^- to j/psi q\bar q will take the leading part. We also find that the energy spectrum for the color-octet j/psi production in process e^+e^- to j/psi q\bar q is very soft, and the mean energy of the produced j/psi is only about 10 GeV~ 20 GeV even at very high energies (e.g. at 1000 GeV). The extraction of color-octet matrix elements from j/psi production in e^+e^- collisions is also discussed.
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
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.
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}
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.
119273979
Entropic corrections and modified Friedmann equations in the emergence of cosmic space
In the emergent cosmic space scenario recently proposed by Padmanabhan, the expansion of the universe is attributed to the difference between the number of degrees of freedom on a holographic surface and the one in the bulk. Based on this idea, we explore the cases where logarithmic and power-law entropic corrections are present, respectively. The previously found modified Friedmann equations are reproduced through an improved proposal, and we show that the same results can be obtained using a generalized expansion law.
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.
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.
118671189
Generalized Hodge dual for torsion in teleparallel gravity
For teleparallel gravity in four dimensions, Lucas and Pereira have shown that its action can be constructed via a generalized Hodge dual for torsion tensor. In this paper, we demonstrate that a direct generalization of this approach to other dimensions fails due to the fact that no generalized Hodge dual operator could be given in general dimensions. Furthermore, if one enforces the definition of a generalized Hodge dual to be consistent with the action of teleparallel gravity in general dimensions, the basic identity for any sensible Hodge dual would require an ad hoc definition for the second Hodge dual operation which is totally unexpected. Therefore, we conclude that at least for the torsion tensor, the observation of Lucas and Pereira only applies to four dimensions.