119301052
Azimuthal asymmetry in SIDIS off nuclei as probe for $\hat q$
Abstract The energy loss parameter q̂ is one of the fundamental transport parameters of hadronic matter. Using the twist-4 collinear approach, we show that the cosφ azimuthal asymmetry in unpolarized semi-inclusive deeply inelastic scattering (SIDIS) off a large nucleus at intermediate transverse momentum is a sensitive observable for its determination. The effect is due to the suppression of the azimuthal asymmetry by final-state multiple scattering.
53325191
Distribution of linearly polarized gluons inside a large nucleus
The distribution of linearly polarized gluons inside a large nucleus is studied in the framework of the color glass condensate. We find that the Weizsacker-Williams distribution saturates the positivity bound at large transverse momenta and is suppressed at small transverse momenta, whereas the dipole distribution saturates the bound for any value of the transverse momentum. We also discuss processes in which both distributions of linearly polarized gluons can be probed.
118347184
Transverse single spin asymmetry in the Drell-Yan process
We revisit the transverse single spin asymmetry in the angular distribution of a Drell-Yan dilepton pair. We study this asymmetry by using twist-3 collinear factorization, and we obtain the same result both in covariant gauge and in the light-cone gauge. Moreover, we have checked the electromagnetic gauge invariance of our calculation. Our final expression for the asymmetry differs from all the previous results given in the literature. The overall sign of this asymmetry is as important as the sign of the Sivers asymmetry in Drell-Yan.
119193850
Exploring the structure of the proton through polarization observables in lp→jet X
We present results for a complete set of polarization observables for jet production in lepton-proton collision, where the final-state lepton is not observed. The calculations are carried out in collinear factorization at the level of Born diagrams. For all the observables we also provide numerical estimates for typical kinematics of a potential future electron-ion collider. On the basis of this numerical study, the prospects for the transverse single target spin asymmetry are particularly promising. This observable is given by a certain quark-gluon correlation function, which has a direct relation to the transverse momentum dependent Sivers parton distribution.
118138920
Color entanglement for γ-jet production in polarized pA collisions
A more reliable treatment of transverse momentum dependent physics and in particular transverse single spin asymmetries is urgently required, e.g. for polarized pA physics including novel effects like color entanglement. We argue that the measurement of azimuthal angular correlations of photons and jets produced in pA collisions provides a direct access to the novel gluon distribution $G_4$ that enters into many such processes.
119185776
Azimuthal asymmetries for quark pair production in pA collisions
We study the azimuthal asymmetries for quark pair production in proton-nucleus collisions using a hybrid approach in which the nucleus is treated in the Color Glass Condensate (CGC) framework while the Lipatov approximation is applied on the proton side. Our treatment goes beyond the large N_c limit. We particularly focus on the so-called correlation limit where the imbalance of the transverse momentum of the quark pair is much smaller than the out-going individual quark transverse momenta. In this kinematic region, a matching between the hybrid approach and a factorization in terms of transverse momentum dependent parton distributions(TMDs) has been found. It is shown which of the various unpolarized and linearly polarized gluon TMD distributions contribute to $\cos 2 \phi$ and $\cos 4 \phi$ modulations of quark pair production.
124323748
Topological Recursions of Eynard–Orantin Type for Intersection Numbers on Moduli Spaces of Curves
We prove that the Virasoro constraints satisfied by the higher Weil–Petersson volumes of moduli spaces of curves are equivalent to Eynard–Orantin topological recursions for some spectral curve. This provides a geometric proof of a result originally derived using a matrix model by Eynard.
119317778
Gopakumar-Vafa BPS invariants, Hilbert schemes and quasimodular forms. I
We prove a closed formula for leading Gopakumar- Vafa BPS invariants of local Calabi-Yau geometries given by the canonical line bundles of toric Fano surfaces. It shares some sim- ilar features with Gottsche-Yau-Zaslow formula: Connection with Hilbert schemes, connection with quasimodular forms, and qua- dratic property after suitable transformation. In Part I of this paper we will present the case of projective plane, more general cases will be presented in Part II. The problem of counting curves in algebraic varieties dates back to the nineteenth century. Classical examples include the famous 27 lines on a cubic surface and the 2875 lines on a quintic 3-fold. Through the interaction with string theory, spectacular progresses in this classi- cal branch of algebraic geometry have been made over the years since 1990's. First of all, Gromov-Witten theory and its various variants have laid the foundation for the modern treatment of many classical enumerative problems and greatly expanded the range of enumerative problems being considered. See (PT) for an introduction to some of the exciting developments. The study of the problems of counting curves in surfaces and Calabi- Yau 3-folds have served both as motivations and applications of Gromov- Witten theory. We will recall some results in these directions in §2 and §3 to serve as motivations for this work. We emphasize on the following three salient features for the curving counting problems for algebraic surfaces: connection with Hilbert schemes, connection with quasimod- ular forms, and quadratic properties of the node polynomials after suit- able transformation. Our main results will show that these features are also shared in the curve counting problems of some noncompact Calabi- Yau 3-folds, arising as the the total space of the canonical line bundles of toric Fano surfaces. 1
115177817
Local Mirror Symmetry for One-Legged Topological Vertex
We prove the Bouchard-Mari\~no Conjecture for the framed one-legged topological vertex by deriving the Eynard-Orantin type recursion relations from the cut-and-join equation satisfied by the relevant triple Hodge integrals. This establishes a version of local mirror symmetry for the local $C^3$ geometry with one $D$-brane.
119173691
Some integrality properties in local mirror symmetry
We prove some integrality properties of the open-closed mirror maps, inverse open-closed mirror maps and mirror curves of some local Calabi-Yau geometries.
201088930
Direct measurement of A(b) and A(c) at the Z(0) pole using a lepton tag
The parity violation parameters Ab and Ac of the Zb anti-b and Zc anti-c couplings have been measured directly, using the polar angle dependence of the Z0-pole polarized cross sections. Bottom and charmed hadrons were tagged via semileptonic decays. Both the muon and electron identification algorithms take advantage of new multivariate techniques, incorporating for the first time information from the SLD Cerenkov Ring Imaging Detector. Based on the 1993-95 SLD sample of 150,000 Z0 decays produced with highly polarized electron beams, we measure: Ab = 0.910 ± 0.068(stat) ± 0.037(syst) Ac = 0.642 ± 0.110(stat) ± 0.063(syst).