67756521
Exclusive production of quarkonia as a probe of the GPD E for gluons
Exclusive quarkonium photo- and electro-production off the nucleon is studied in the framework of generalized parton distributions (GPDs). The short distance part of the process is treated at leading order in perturbative Quantum Chromodynamics. The main focus is on the GPD E for gluons. On the basis of different models for E we estimate the transverse target spin asymmetry for typical kinematics of a future Electron Ion Collider. We also explore the potential of measuring the polarization of the recoil nucleon.
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.
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.
119690858
SINGLE SPIN ASYMMETRIES IN INCLUSIVE DIS AND MULTI-PARTON CORRELATIONS IN THE NUCLEON
Transverse single spin asymmetries in inclusive deep-inelastic lepton-nucleon scattering can be generated through multi-photon exchange between the leptonic and the hadronic part of the process. Here we consider two-photon exchange, and mainly focus on the transverse target spin asymmetry. In particular, we investigate the case where two photons couple to different quarks. Such a contribution involves a quark-photon-quark correlator in the nucleon, which has a (model-dependent) relation to the Efremov-Teryaev-Qiu-Sterman quark-gluon-quark correlator TF. Using different parameterizations for TF we compute the transverse target spin asymmetry for both a proton and a neutron target, and compare the results to recent experimental data. Potential implications on our general understanding of single spin asymmetries in hard scattering processes are discussed as well.
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.
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.
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.
18784194
Localizations on Moduli Spaces and Free Field Realizations of Feynman Rules
We prove Iqbal's conjecture on the relationship between the free energy of closed string theory in local toric geometry and the Wess-Zumino-Witten model. This is achieved by first reformulating the calculations of the free energy by localization techniques in terms of suitable Feynman rule, then exploiting a realization of the Feynman rule by free bosons. We also use a formula of Hodge integrals conjectured by the author and proved jointly with Chiu-Chu Melissa Liu and Kefeng Liu.
119303884
Integrality Properties of Variations of Mahler Measures
We propose some conjectures on the integrality properties related to the variation of Mahler measures, inspired by the results in the elliptic curve case by Rodriguez Villegas, Stienstra and Zagier.
2897011
A formula of two-partition Hodge integrals
JMg,n where tpi = ci(L?) is the first Chern class of L?, and Xj = Cj(E) is the j-th Chern class of the Hodge bundle. The study of Hodge integrals is an important part of intersection theory on Mg,n> Hodge integrals also naturally arise when one computes Gromov-Witten invariants by localization techniques. For example, the following generating series of Hodge integrals arises when one computes local invariants of a toric Fano surface in a Calabi-Yau 3-fold by virtual localization [33]:
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