118319655
Polarized $J/\psi$ production in deep inelastic scattering at HERA
We perform a calculation on the polarization of J/psi production in deep inelastic scattering in the HERA energy range. For the inclusive production distributions, we find that the color-singlet contributions are consistent with the experimental data in the major region of z (z>0.4). Only in low z regions, there are some hints of the need of the color-octet contributions to describe the experimental data. For the polarization of J/psi in DIS processes, we find the parameter alpha changes with Q^2. Especially, at higher Q^2, difference on alpha between color-singlet and color-octet contributions become more distinctive. In the two regions of lower and larger z, the polarization parameter alpha have different features. These properties can provide important information on the polarization mechanism for J/psi production.
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.
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.
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}
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
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.
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.
119257303
F(T) GRAVITY FROM HOLOGRAPHIC RICCI DARK ENERGY MODEL WITH NEW BOUNDARY CONDITIONS
Commonly used boundary conditions in reconstructing f(T) gravity from holographic Ricci dark energy (RDE) model are found to cause some problem, we therefore propose new boundary conditions in this paper. By reconstructing f(T) gravity from the RDE with these new boundary conditions, we show that the new ones are better than the present commonly used ones since they can give the physically expected information, which is lost when the commonly used ones are taken in the reconstruction, of the resulting f(T) theory. Thus, the new boundary conditions proposed here are more suitable for the reconstruction of f(T) gravity.
119293239
Harrison Metrics for the Schwarzschild Black Hole
Based on the hidden conformal symmetry, some authors have proposed a Harrison metric for the Schwarzschild black hole. We give a procedure which can generate a family of Harrison metrics starting from a general set of SL(2, R) vector fields. By analogy with the subtracted geometry of the Kerr black hole, we find a new Harrison metric for the Schwarzschild case. Its conformal generators are also investigated using the Killing equations in the near-horizon limit.
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.