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.
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.
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.
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.
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.
119353308
Parton distributions in light-cone gauge: where are the final-state interactions?
We show that the final-state interaction effects in the single target spin asymmetry discovered by Brodsky et al. can be reproduced by either a standard light-cone gauge definition of the parton distributions with a prescription for the light-cone singularities consistent with the light-cone gauge link, or a modified light-cone gauge definition with a gauge link involving the gauge potential at the spatial infinity.
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
54205431
Accessing tri-gluon correlations in the nucleon via the single spin asymmetry in open charm production
We calculate the single transverse-spin asymmetry for open charm production in pp collisions within the QCD collinear factorization approach. We include contributions from both twist-three quark-gluon and tri-gluon correlation functions. We find that the quark-gluon correlation functions alone generate only a very small asymmetry for open charm production in the kinematic region of current interest at RHIC, so that the observation of any significant single-spin asymmetry would be a clear indication of the presence of tri-gluon correlations inside a polarized proton. We furthermore demonstrate that the tri-gluon contribution could be very different for the production of D and \bar{D} mesons. These features make the single spin asymmetry in open charm production in polarized pp collisions at RHIC an excellent probe of tri-gluon correlation functions.
21184220
Generalized counting rule for hard exclusive processes.
We derive a generalized counting rule for hard exclusive processes involving parton orbital angular momentum and hadron helicity flip. We start with a systematic way to enumerate the Fock components of a hadronic light-cone wave function with n partons and orbital angular momentum projection l(z). We show that the wave-function amplitude psi(n)(x(i),k(i perpendicular ),l(zi)) has a leading behavior 1/(k(2)( perpendicular ))[n(+|l(z)|+min(n(')+|l(')(z)|)]/2-1) when all parton transverse momenta are uniformly large, where n(') and l(')(z) are the number of partons and orbital angular momentum projection, respectively, of an amplitude that mixes under renormalization. Besides the generalized counting rule, the result can be used as a constraint in modeling the hadronic light-cone wave functions.
123146349
The NLO inclusive forward hadron production in pA collisions
Abstract Recently, the one-loop factorization for inclusive hadron productions in pA collisions in the saturation formalism has been established via the complete next-to-leading order calculation. The differential cross section is written into a factorization form in the coordinate space at the next-to-leading order, while the naive form of the convolution in the transverse momentum space does not hold. The rapidity divergence with small-x dipole gluon distribution of the nucleus is factorized into the energy evolution of the dipole gluon distribution function, which is known as the Balitsky–Kovchegov equation. Furthermore, the collinear divergences associated with the incoming parton distribution of the nucleon and the outgoing fragmentation function of the final state hadron are factorized into the splittings of the associated parton distribution and fragmentation functions, which allows us to reproduce the well-known DGLAP equation. The hard coefficient function, which is finite and free of divergence of any kind, is evaluated at one-loop order. This result is important, not only for the phenomenological applications to the inclusive hadron production in p-A collisions at RHIC and future LHC experiment, but also for theoretically promoting the rigorous developments towards factorizations in small-x physics.