A5001512916- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Superconducting Materials and Applications
- Dark Matter and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Distributed and Parallel Computing Systems
- Particle Accelerators and Free-Electron Lasers
- Computational Physics and Python Applications
- Cosmology and Gravitation Theories
- Particle Detector Development and Performance
- Medical Imaging Techniques and Applications
- Advanced NMR Techniques and Applications
- Magnetic confinement fusion research
- International Science and Diplomacy
- Scientific Research and Discoveries
- Neutrino Physics Research
- Particle accelerators and beam dynamics
- Black Holes and Theoretical Physics
- Pulsars and Gravitational Waves Research
- Radioactive element chemistry and processing
- Nuclear physics research studies
- Nuclear Materials and Properties
- Astrophysics and Cosmic Phenomena
- Quantum, superfluid, helium dynamics
University of Tübingen
2015-2024
Argonne National Laboratory
1966-2024
University of Buenos Aires
2007-2022
Fundación Ciencias Exactas y Naturales
2022
National University of General San Martín
2019
International Center for Advanced Studies
2019
Instituto de Física Teórica
2017
University of Regensburg
2003-2017
Stony Brook University
1999-2016
Los Alamos National Laboratory
2016
This White Paper presents the science case of an Electron-Ion Collider (EIC), focused on structure and interactions gluon-dominated matter, with intent to articulate it broader nuclear community. It was commissioned by managements Brookhaven National Laboratory (BNL) Thomas Jefferson Accelerator Facility (JLab) objective presenting a summary scientific opportunities goals EIC as follow-up 2007 NSAC Long Range plan. document is culmination community-wide effort in following series workshops...
Polarized deep inelastic scattering (DIS) data are analyzed in leading and next-to-leading order of QCD within the common ``standard'' scenario polarized parton distributions with a flavor-symmetric light sea (antiquark) distribution $\ensuremath{\delta}\overline{q},$ completely ${\mathrm{SU}(3)}_{f}$ broken ``valence'' totally flavor-asymmetric densities $(\ensuremath{\delta}\ifmmode \bar{u}\else...
We discuss techniques and results for the extraction of nucleon's spin-dependent parton distributions their uncertainties from data polarized deep-inelastic lepton-nucleon proton-proton scattering by means a global QCD analysis. Computational methods are described that significantly increase speed required calculations to level allows one perform full analysis consistently at next-to-leading order accuracy. examine how various sets help constrain different aspects quark, antiquark, gluon...
We discuss the impact of recent high-statistics RHIC data on determination gluon polarization in proton context a global QCD analysis polarized parton distributions. find clear evidence for non-vanishing gluons region momentum fraction and at scales mostly probed by data. Although information from low fractions is presently lacking, this finding suggestive significant contribution spin to spin, thereby limiting amount orbital angular required balance budget.
This report is based on a ten-week program Gluons and the quark sea at high-energies, which took place Institute for Nuclear Theory (INT) in Seattle Fall 2010. The principal aim of was to develop sharpen science case an Electron-Ion Collider (EIC), facility that will be able collide electrons positrons with polarized protons light heavy nuclei high energies, offering unprecedented possibilities in-depth studies quantum chromodynamics (QCD). organized around following four major themes: (i)...
We present a new analysis of the helicity parton distributions nucleon. The takes into account available data from inclusive and semi-inclusive polarized deep inelastic scattering, as well proton-proton (p-p) scattering at RHIC. For first time, all theoretical calculations are performed fully next-to-leading order (NLO) perturbative QCD, using method that allows incorporation NLO corrections in very fast efficient way analysis. find evidence for rather small gluon polarization nucleon, over...
A next-to-leading-order QCD analysis of spin asymmetries and structure functions in polarized deep inelastic lepton-nucleon scattering is presented within the framework radiative parton model. consistent NLO formulation ${\mathit{Q}}^{2}$ evolution distributions yields two sets plausible spin-dependent conventional MS factorization scheme. They respect fundamental positivity constraints down to low resolution scale ${\mathit{Q}}^{2}$=${\mathrm{\ensuremath{\mu}}}_{\mathrm{NLO}}^{2}$=0.34...
We calculate the complete $O(\ensuremath{\alpha}{\ensuremath{\alpha}}_{s}^{2})$ corrections to inclusive cross section for hadronic prompt photon production, both unpolarized case and of longitudinal polarization incoming hadrons. present analytical expressions all our results.
We determine the valence parton distribution function of pion by performing a new analysis data for Drell-Yan process $\pi^- N\to \mu^+\mu^-X$. Compared to previous analyses, we include next-to-leading-logarithmic threshold resummation effects in calculation cross section. As result these, find considerably softer at high momentum fractions $x$ than obtained next-to-leading order line with expectations based on perturbative-QCD counting rules or Dyson-Schwinger equations.
This White Paper presents the science case of an Electron-Ion Collider (EIC), focused on structure and interactions gluon-dominated matter, with intent to articulate it broader nuclear community. It was commissioned by managements Brookhaven National Laboratory (BNL) Thomas Jefferson Accelerator Facility (JLab) objective presenting a summary scientific opportunities goals EIC as follow-up 2007 NSAC Long Range plan. document is culmination community-wide effort in following series workshops...
We present a calculation for single-inclusive large-${p}_{T}$ pion production in longitudinally polarized $\mathrm{pp}$ collisions next-to-leading order QCD. choose an approach where fully analytical expressions the underlying partonic hard-scattering cross sections are obtained. simultaneously rederive corresponding corrections to unpolarized scattering and confirm results existing literature. Our allow calculate double-spin asymmetry ${A}_{\mathrm{LL}}^{\ensuremath{\pi}}$ this process at...
Using lepton-pair production in hadron-hadron collisions as an example, we explore the relation between two well-known mechanisms for single-transverse-spin asymmetries hard processes: twist-three quark-gluon correlations when pair's transverse momentum is large, q perpendicular >> Lambda QCD, and time-reversal-odd transverse-momentum-dependent parton distributions much less than mass. We find that, although each have their own domain of validity, they describe same physics kinematic region...
We study the single-spin (left-right) asymmetry in single-inclusive pion production hadronic scattering. This is power-suppressed transverse momentum of produced and can be analyzed terms twist-three parton correlation functions proton. present new calculations corresponding partonic hard-scattering that include so-called ``nonderivative'' contributions not previously considered literature. find a remarkably simple structure results. also brief phenomenological spin asymmetry, taking into...
We study single-spin asymmetries in semi-inclusive deep inelastic scattering with transversely polarized target. Based on the QCD factorization approach, we consider Sivers and Collins contributions to asymmetries. fit simple parameterizations for functions recent HERMES data, compare results from COMPASS. Using fitted functions, predict single transverse spin various processes $pp$ collisions at RHIC, including Drell-Yan process angular correlations dijet jet-plus-photon production. These...
We study the QCD charge asymmetry in $t\overline{t}$ production at Tevatron. investigate role of higher orders perturbation theory by considering resummation potentially large logarithmic corrections that arise near partonic threshold. This requires us to employ rapidity-dependent anomalous dimension matrices describe color mixing due soft-gluon emission both quark- and gluon-initiated processes. The appears directly resummed cross section next-to-leading logarithm (NLL), we find first-order...
The ${k}_{\ensuremath{\perp}}$ moment of a quark's Sivers function is known to be related the corresponding twist-three quark-gluon correlation ${T}_{q,F}(x,x)$. two functions have been extracted from data for single-spin asymmetries in semi-inclusive deep-inelastic scattering and single-inclusive hadron production $pp$ collisions, respectively. Performing consistent comparison functions, we find that they show ``sign mismatch'': while magnitude roughly consistent, has opposite sign...
Time and again, spin has been a key element in the exploration of fundamental physics. Spin-dependent observables have often revealed deficits assumed theoretical framework led to novel developments concepts. Spin is exploited many parity-violating experiments searching for physics beyond Standard Model or studying nature nucleon-nucleon forces. The RHIC program plays special role this grand scheme: it uses study how complex many-body system such as proton arises from dynamics QCD. Many...
We propose the lepton-jet correlation in deep inelastic scattering as a unique tool for tomography of nucleons and nuclei at electron-ion collider (EIC). The azimuthal angular between final state lepton jet depends on transverse momentum dependent quark distributions. take example single spin asymmetries to show sensitivity Sivers function. When is studied lepton-nucleus collisions, broadening effects can be used explore cold nuclear matter effects. These features make correlations an...
We implement a Monte Carlo sampling strategy to extract helicity parton densities and their uncertainties from reference set of longitudinally polarized scattering data, chosen be that used in the DSSV14 global analysis. Instead adopting simplest possible functional forms for distributions imposing certain restrictions on parameter space order constrain them, we employ redundant, flexible parametrizations fit them large number replicas existing data. The optimum its uncertainty estimates are...
Colliding beams of 70% polarized protons at up to $\sqrt{s}$=500 GeV, with high luminosity, L=2$\times10^{\rm 32}$ cm$^{-2}$sec$^{-1}$, will represent a new and unique laboratory for studying the proton. RHIC-Spin be first polarized-proton collider capable copious production jets, directly produced photons, $W$ $Z$ bosons. Features include direct precise measurements polarization gluons $\bar{u}$, $\bar{d}$, $u$, $d$ quarks in Parity violation searches physics beyond standard model...
We analyze experimental data for the production of \ensuremath{\Lambda} baryons in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation terms scale-dependent, QCD-evolved, fragmentation functions. Apart from vast majority which polarization an observed was not determined, we also consider recent CERN LEP measurements longitudinal \ensuremath{\Lambda}'s produced on $Z$ resonance. Such correspond to spin-dependent functions \ensuremath{\Lambda}. point out that present are insufficient satisfactorily fix...
We perform a new calculation of the polarized next-to-leading order splitting functions, using method developed by Curci, Furmanski and Petronzio. confirm results recent Mertig van Neerven.
We present a phenomenological application of the joint resummation formalism to electroweak annihilation processes at measured boson momentum ${Q}_{T}.$ This simultaneously resums next-to-leading logarithmic accuracy large threshold and recoil corrections partonic scattering. invert impact parameter transform using previously described analytic continuation procedure. leads well-defined, resummed perturbative cross section for all nonzero ${Q}_{T},$ which can be compared carried out directly...
We study the single-transverse-spin asymmetry for Drell-Yan process. consider production of lepton pair at large transverse momentum, ${q}_{\ensuremath{\perp}}\ensuremath{\sim}Q$, where $Q$ is pair's mass. The spin then higher twist and may be generated by twist-three quark-gluon correlation functions. Expanding result ${q}_{\ensuremath{\perp}}\ensuremath{\ll}Q$, we make contact with transverse-momentum-dependent QCD factorization involving so-called Sivers find that two mechanisms,...