Conveners
3D Structure of the Nucleon: TMDs
- Bakur Parsamyan (TO)
- James Drachenberg (Abilene Christian University)
- Alessandro Bacchetta (PV)
3D Structure of the Nucleon: TMDs
- Alessandro Bacchetta (PV)
- Bakur Parsamyan (TO)
- James Drachenberg (Abilene Christian University)
3D Structure of the Nucleon: TMDs
- Alessandro Bacchetta (PV)
- Bakur Parsamyan (TO)
- James Drachenberg (Lamar University)
3D Structure of the Nucleon: TMDs
- Alessandro Bacchetta (PV)
- Bakur Parsamyan (TO)
- James Drachenberg (Abilene Christian University)
3D Structure of the Nucleon: TMDs
- James Drachenberg (Abilene Christian University)
- Alessandro Bacchetta (PV)
- Bakur Parsamyan (TO)
3D Structure of the Nucleon: TMDs
- Bakur Parsamyan (TO)
- Alessandro Bacchetta (PV)
- James Drachenberg (Abilene Christian University)
3D Structure of the Nucleon: TMDs
- Bakur Parsamyan (TO)
- Alessandro Bacchetta (PV)
- James Drachenberg (Abilene Christian University)
3D Structure of the Nucleon: TMDs
- James Drachenberg (Abilene Christian University)
- Alessandro Bacchetta (PV)
- Bakur Parsamyan (TO)
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Francesco Murgia (CA)10/09/2018, 14:303D Structure of the Nucleon: TMDsParallel SessionsTransverse single spin asymmetries for hadron production in polarized semi-inclusive deeply inelastic scattering (SIDIS) are nowadays one of the main source of information on transversity, the quark Sivers distributions and the Collins fragmentation function, and on their transverse momentum dependence. However, in SIDIS the transverse momentum of the final hadron, that is the quantity...Go to contribution page
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Anna Martin (TS)10/09/2018, 14:553D Structure of the Nucleon: TMDsParallel SessionsThe COMPASS Collaboration has recently measured the Sivers asymmetries weighted with the hadron transverse momentum, analyzing the high statistics data sample collected in 2010 to measure semi-inclusive deep inelastic scattering on a transversely polarised proton target. These asymmetries provide direct information on the Sivers function, which is one of the most studied transverse momentum...Go to contribution page
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Jan Matousek (University and INFN Trieste, Italy)10/09/2018, 15:203D Structure of the Nucleon: TMDsParallel SessionsIn 2015 at the COMPASS experiment at CERN a pion beam with momentum of 190 GeV/c interacted with a transversely polarised NH_3 target. Muon pairs produced in the DrellโYan process were detected. In addition to the extraction of the transverse spin asymmetries (TSAs) from this data, a complementary analysis of the TSAs weighted by powers of the dimuon momentum q_T has been done and will be...Go to contribution page
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Prof. Carl Gagliardi (Texas A&M University)10/09/2018, 15:453D Structure of the Nucleon: TMDsParallel SessionsThe STAR Collaboration at RHIC is exploring the partonic origin of the proton spin with a broad range of measurements in polarized pp collisions. STAR measurements of the transverse single-spin asymmetry, $A_N$, for $W$ boson production provide the first experimental investigation of the non-universality of the Sivers function. Precise follow-up measurements of $A_N$ for direct photon...Go to contribution page
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Dr Giuseppe Bozzi (PV)10/09/2018, 16:403D Structure of the Nucleon: TMDsParallel SessionsWithin the framework of transverse-momentum-dependent factorization, we investigate for the first time the impact of a flavor-dependent intrinsic transverse momentum of quarks on the production of W bosons in hadronic collisions. We study the transverse-mass, lepton transverse momentum, and missing transverse momentum distributions of the Wโdecay products by means of a template-fit technique...Go to contribution page
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Marco Mirazita (LNF)10/09/2018, 17:053D Structure of the Nucleon: TMDsParallel SessionsIn January 2018, the CLAS12 spectrometer has started taking data using the 10.6 GeV, higly polarized, electron beam on a liquid hydrogen unpolarized target, at a luminosity as high as 10^35 cm^-2 s^-1, about one order of magnitude higher than during the 6 GeV era with the CLAS spectrometer. The high beam quality combined with the large acceptance of CLAS12 will allow for the first time to...Go to contribution page
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78. Nuclear Dependence of Transverse Single-Spin Asymmetries in Polarized $p$+$A$ Collisions at RHICDr Stephen Pate (New Mexico State University)10/09/2018, 17:303D Structure of the Nucleon: TMDsParallel SessionsLarge transverse single-spin asymmetries (TSSA) in hadron production at forward rapidity have been observed in polarized $p$+$p$ interactions for many decades, over a large range of center-of-mass energies, and have led to the investigation of spin-momentum correlations such as the Sivers and Collins effects. In the last few years, it has been discovered at RHIC that these single-spin...Go to contribution page
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Mr Minho Kim (Korea University/ RIKEN)10/09/2018, 17:553D Structure of the Nucleon: TMDsParallel SessionsNon-zero transverse single spin asymmetry, AN, of forward pi0 production in the pseudo rapidity range of 3<eta<4 has been measured by various experiments so far and usually interpreted by hard process mechanism between polarized and unpolarized proton collisions. However, no clue can be found yet if there is a potential contribution from the soft process and recently larger AN was also...Go to contribution page
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Dr Marco Radici (PV)11/09/2018, 14:303D Structure of the Nucleon: TMDsParallel SessionsWe present the first extraction of the transversity distribution based on the global analysis of pion-pair production in deep-inelastic scattering and in proton-proton collisions with one transversely polarized proton. The extraction relies on the knowledge of di-hadron fragmentation functions, which are taken from the analysis of electron-positron annihilation data. We compute the tensor...Go to contribution page
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Prof. Franco Bradamante (INFN, Trieste Section)11/09/2018, 14:553D Structure of the Nucleon: TMDsParallel SessionsSince 2005, measurements of Collins and Sivers asymmetries from the HERMES and COMPASS experiments have allowed to assess that the transversity and the Sivers PDF are different from zero and measurable in semi-inclusive DIS on transversely polarized targets. Most of the data were collected on proton targets, only few data were collected in the early phase of the COMPASS experiment on a...Go to contribution page
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Dr Fernanda Steffens (DESY - Zeuthen)11/09/2018, 15:203D Structure of the Nucleon: TMDsParallel SessionsUsing the quark quasi-distribution approach, we present the first direct calculation of the transversity parton distribution function within the nucleon from lattice QCD. The calculation is performed using simulations with the light quark mass fixed to its physical. We employ non-perturbative renormalization to subtract the linear and log divergences present in the bare matrix elements, and...Go to contribution page
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Michael Engelhardt (New Mexico State University)11/09/2018, 15:453D Structure of the Nucleon: TMDsParallel SessionsQuark orbital angular momentum (OAM) in the proton can be calculated directly if a Wigner function encoding the simultaneous distribution of quark transverse positions and momenta is given. This distribution can be accessed via proton matrix elements of a quark bilocal operator (the separation in which is Fourier conjugate to the quark momentum) featuring a momentum transfer (which is...Go to contribution page
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Cristian Pisano (CA)11/09/2018, 16:403D Structure of the Nucleon: TMDsParallel SessionsWithin the color gauge invariant generalized parton model (CGI-GPM), that includes initial- and final-state interactions in a TMD formalism, we present the complete results, at leading-order, for transverse single-spin asymmetries in the inclusive hadroproduction of pions, direct photons, D mesons and quarkonia.Go to contribution page
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Umberto D'Alesio (CA)11/09/2018, 17:053D Structure of the Nucleon: TMDsParallel SessionsWithin the so-called color gauge invariant generalized parton model (CGI-GPM), we will discuss how a phenomenological analysis of available SSA data for pion, D meson and J/psi production in pp collisions can be used to put the first constraints on the two universal types of gluon Sivers function. A comparison with the simpler generalized parton model, as well as predictions for SSAs in...Go to contribution page
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Dr Sook Hyun Lee (Iowa State University)11/09/2018, 17:303D Structure of the Nucleon: TMDsParallel SessionsThe J/Psi, a bound state of charm and anti-charm quark with spin 1, decays into lepton pairs with a large branching ratios. Its production in polarized and unpolarized p+p collisions sheds light on different aspects of QCD. At RHIC energies, charmonium production in $p$+$p$ collisions is dominated by gluon-gluon interaction. As a result, measurements of the TSSA in polarized $p$+$p$ collisions...Go to contribution page
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Nicole Lewis (PHENIX)11/09/2018, 17:553D Structure of the Nucleon: TMDsParallel SessionsTransverse single-spin asymmetries (TSSAs) of proton-proton collisions have a long history of revealing the richness of QCD. They were originally measured in fixed target experiments and ignored for a couple decades because it was assumed that they came incalculable soft QCD interactions. But they have been found to persist in collisions up to \sqrt{s} = 510 GeV, well into the perturbative...Go to contribution page
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Mr Andrea Moretti (University of Trieste / INFN)12/09/2018, 14:303D Structure of the Nucleon: TMDsParallel SessionsIn 2016 and 2017 the COMPASS Collaboration has measured 160 GeV/c muon scattering on a 2.5 m long liquid Hydrogen target. The main goal of the measurement was to access GPDs via the deeply virtual Compton Scattering (DVCS) process, but in parallel SIDIS data were collected to investigate the azimuthal modulations of the hadron lepto-production cross-section. In this talk we present preliminary...Go to contribution page
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Albi Kerbizi (TS)12/09/2018, 14:553D Structure of the Nucleon: TMDsParallel SessionsThe measurement of azimuthal modulations in hadron leptoproduction on unpolarised nucleons allows to get information on the intrinsic transverse momentum of quarks in a nucleon through both the Cahn effect and the Boer-Mulders function. In particular the latter describes a possible correlation between the intrinsic transverse momentum and the transverse spin of the quarks of an unpolarized...Go to contribution page
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Dr Alexey Vladimirov (Regensburg University)12/09/2018, 15:203D Structure of the Nucleon: TMDsParallel SessionsEvolution of transverse momentum dependent distributions (TMD evolution) is an evolution with respect to two scales: the renormalization and rapidity scales. The double scale evolution grants a freedom in the definition of physical observables, which naively could lead to ambiguous results. We show that the double-evolution picture has a natural interpretation in terms of evolution potential,...Go to contribution page
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Mr Daniel Gutiรฉrrez Reyes (Complutense University of Madrid)12/09/2018, 15:453D Structure of the Nucleon: TMDsParallel SessionsThe factorization theorem for DY and semi-inclusive DIS holds for all leading twist transverse momentum distributions. However a QCD perturbative calculation shows several important characteristics of spin-dependent distributions. We consider all the different spin-dependent distributions which can be matched onto integrated twist-2 functions, focusing on the transversity and pretzelosity...Go to contribution page
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Fulvio Piacenza (PV)12/09/2018, 16:403D Structure of the Nucleon: TMDsParallel SessionsIn this talk, we discuss the transverse momentum distribution of Drell-Yan lepton pairs in fixed-target Drell-Yan experiments. We show that fixed-order theory underestimates data at large qT, by an amount that cannot be explained by perturbative truncation errors nor PDF uncertainties. We consider a modification of the standard collinear formalism that includes the effect of intrinsic...Go to contribution page
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Jose Osvaldo Gonzalez Hernandez (TO)12/09/2018, 17:053D Structure of the Nucleon: TMDsParallel SessionsThe most recent SIDIS measurements have challenged our understanding of factorization theorems in QCD. In order to perform reliable extractions of transverse momentum dependent functions (TMDs) it is essential to understand the extent to which the errors of factorization are under control. In this talk I will discuss about the issues encountered when comparing theory and experiment. I will...Go to contribution page
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Nobuo Sato (Jefferson Lab)12/09/2018, 17:303D Structure of the Nucleon: TMDsParallel SessionsIn this talk I will discuss recent progress to understand the large qT spectrum in SIDIS and DY.Go to contribution page
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Francesco Hautmann (University of Oxford)12/09/2018, 17:553D Structure of the Nucleon: TMDsParallel SessionsCollinear and transverse momentum dependent (TMD) parton densities are obtained from fits to precision measurements of deep inelastic scattering (DIS) cross sections at HERA. The parton densities are evolved by DGLAP evolution with next-to-leading-order (NLO) splitting functions using the parton branching method, allowing one to determine simultaneously collinear and TMD densities for all...Go to contribution page
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Ms Sabrina Cotogno (Vrije Universiteit Amsterdam and Nikhef)13/09/2018, 14:303D Structure of the Nucleon: TMDsParallel SessionsIn processes where two quarks are extracted from the proton to enter two separate hard scatterings (double parton scattering), the interparton correlations can have an impact on the size of the cross section and significantly alter the distributions of particles in the final state. In this work, we employ different models for the double parton distributions (DPDs) to study the quantum...Go to contribution page
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Simone Rodini (PV & INFN)13/09/2018, 14:553D Structure of the Nucleon: TMDsParallel SessionsHigher-twist transverse-momentum dependent parton distributions (TMDs) go beyond the parton model description of a proton as they describe correlations between quarks and gluons. Higher-twist TMDs, however, turn out to be very elusive objects, as they are difficult to extract from experimental data. Twist-3 distributions can be decomposed as a sum of different contributions. In general, these...Go to contribution page
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Caroline Riedl (University of Illinois at Urbana-Champaign)13/09/2018, 15:203D Structure of the Nucleon: TMDsParallel SessionsAn overview of pion-induced Drell-Yan (DY) scattering at COMPASS is given. In 2015, COMPASS was scattering a 190 GeV pion beam off a transversely polarized proton target and unpolarized nuclear targets. The Sivers asymmetry, and other spin-dependent azimuthal asymmetry amplitudes, were extracted from these data. The Sivers asymmetry is of particular interest since it is expected to change sign...Go to contribution page
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Dr Miguel Echevarria (INFN Pavia)13/09/2018, 16:403D Structure of the Nucleon: TMDsParallel SessionsA fixed-target experiment using the LHC beams with a polarized target would offer a unique opportunity to study the internal structure of the nucleon. Recent studies have shown that a number of spin and azimuthal asymmetries are large enough to be precisely measured, allowing to constrain several non-perturbative functions which encode the three-dimensional spin structure of the nucleon, as...Go to contribution page
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Prof. Gary Goldstein (Tufts University)13/09/2018, 17:053D Structure of the Nucleon: TMDsParallel SessionsGluon pdfโs, GPDโs and TMDโs play a significant role in an array of scattering processes, including SIDIS, DVCS, exclusive meson electroproduction and p p scattering. Spin dependent gluon distributions can lead to distinctive features in the angular dependences and asymmetries of the scattering processes. Of particular interest are heavy quark production processes, wherein spin observables of...Go to contribution page
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Qinghua Xu (Shandong University)13/09/2018, 17:553D Structure of the Nucleon: TMDsParallel SessionsThe longitudinal or transverse spin transfer to Lambda and anti-Lambda hyperons in polarized proton-proton collisions is expected to be sensitive to the helicity or transversity distributions of strange and anti-strange quarks of the proton, and to the corresponding polarized fragmentation function. We report the first measurement of the transverse spin transfer to Lambda and anti-Lambda along...Go to contribution page