scholarly journals Studies of Transverse-Momentum-Dependent Distributions with a Fixed-Target ExpeRiment Using the LHC Beams (AFTER@LHC)

2016 ◽  
Vol 40 ◽  
pp. 1660107 ◽  
Author(s):  
L. Massacrier ◽  
M. Anselmino ◽  
R. Arnaldi ◽  
S. J. Brodsky ◽  
V. Chambert ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Nuclear Physics ◽  
Transverse Spin ◽  
Fixed Target ◽  
Transverse Momentum Dependent ◽  
Spin Asymmetries ◽  
Bent Crystal ◽  
Target Mode ◽  
Target Experiment ◽  
Fixed Target Experiment

We report on the studies of Transverse-Momentum-Dependent distributions (TMDs) at a future fixed-target experiment –AFTER@LHC– using the [Formula: see text] or Pb ion LHC beams, which would be the most energetic fixed-target experiment ever performed. AFTER@LHC opens new domains of particle and nuclear physics by complementing collider-mode experiments, in particular those of RHIC and the EIC projects. Both with an extracted beam by a bent crystal or with an internal gas target, the luminosity achieved by AFTER@LHC surpasses that of RHIC by up to 3 orders of magnitude. With an unpolarised target, it allows for measurements of TMDs such as the Boer-Mulders quark distributions and the distribution of unpolarised and linearly polarised gluons in unpolarised protons. Using polarised targets, one can access the quark and gluon Sivers TMDs through single transverse-spin asymmetries in Drell-Yan and quarkonium production. In terms of kinematics, the fixed-target mode combined with a detector covering [Formula: see text] allows one to measure these asymmetries at large [Formula: see text] in the polarised nucleon.

COMPASS RESULTS ON TMD OBSERVABLES

2012 ◽  
Vol 20 ◽  
pp. 9-18
Author(s):  
◽  
ANNA MARTIN
Keyword(s):  
Transverse Momentum ◽  
Inelastic Scattering ◽  
Deep Inelastic Scattering ◽  
Muon Beam ◽  
Transverse Spin ◽  
Scientific Program ◽  
Fixed Target ◽  
Transverse Structure ◽  
Target Experiment ◽  
Fixed Target Experiment

The study of the transverse spin and transverse momentum structure of the nucleon is an important part of the scientific program of COMPASS, a fixed target experiment taking data at the CERN SPS since 2002. In these ten years COMPASS has produced a number of interesting results by measuring the forward going hadrons produced in deep inelastic scattering of a 160 GeV muon beam off polarized deuteron and proton targets. The COMPASS contribution to the understanding of the transverse structure of the nucleon, and the possible future contributions, are briefly reviewed here.

TRANSVERSE SPIN AND TRANSVERSE MOMENTUM EFFECTS AT COMPASS

2009 ◽  
Vol 24 (35n37) ◽  
pp. 3015-3024 ◽  
Author(s):  
FRANCO BRADAMANTE
Keyword(s):  
Transverse Momentum ◽  
Muon Beam ◽  
Transverse Spin ◽  
Fixed Target ◽  
Deuteron Target ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Polarized Target ◽  
Single Spin Asymmetries ◽  
Target Experiment

The study of transverse spin and transverse momentum effects is part of the scientific program of COMPASS, a fixed target experiment at the CERN SPS. For these studies, a 160 GeV/c momentum muon beam is scattered on a transversely polarized nucleon target, and the scattered muon and the forward going hadrons produced in DIS processes are reconstructed and identified in a magnetic spectrometer. The measurements have been performed on a deuteron target in 2002, 2003 and 2004, and on a proton target in 2007. The main results obtained measuring single spin asymmetries are reviewed, with particular emphasis on the most recent proton measurements. After two years of spectroscopy measurements with hadron beams, in 2008 and 2009, the Collaboration will resume measurements with the muon beam and a transversely polarized target in 2010.

scholarly journals Feasibility Studies for Quarkonium Production at a Fixed-Target Experiment Using the LHC Proton and Lead Beams (AFTER@LHC)

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
L. Massacrier ◽  
B. Trzeciak ◽  
F. Fleuret ◽  
C. Hadjidakis ◽  
D. Kikola ◽  
...  
Keyword(s):  
Feasibility Studies ◽  
Fixed Target ◽  
Detection Techniques ◽  
Target Mode ◽  
Quarkonium Production ◽  
Target Experiment ◽  
Conventional Detection ◽  
Fixed Target Experiment

Being used in the fixed-target mode, the multi-TeV LHC proton and lead beams allow for studies of heavy-flavour hadroproduction with unprecedented precision at backward rapidities, far negative Feynman-x, using conventional detection techniques. At the nominal LHC energies, quarkonia can be studied in detail inp+p,p+d, andp+Acollisions atsNN≃115 GeV and in Pb +pand Pb +Acollisions atsNN≃72 GeV with luminosities roughly equivalent to that of the collider mode that is up to 20 fb−1 yr−1inp+pandp+dcollisions, up to 0.6 fb−1 yr−1inp+Acollisions, and up to 10 nb−1 yr−1in Pb +Acollisions. In this paper, we assess the feasibility of such studies by performing fast simulations using the performance of a LHCb-like detector.

scholarly journals Feasibility Studies for Single Transverse-Spin Asymmetry Measurements at a Fixed-Target Experiment Using the LHC Proton and Lead Beams (AFTER@LHC)

2017 ◽  
Vol 58 (4) ◽  
Author(s):  
Daniel Kikoła ◽  
Miguel García Echevarria ◽  
Cynthia Hadjidakis ◽  
Jean-Philippe Lansberg ◽  
Cédric Lorcé ◽  
...  
Keyword(s):  
Spin Asymmetry ◽  
Feasibility Studies ◽  
Transverse Spin ◽  
Fixed Target ◽  
Target Experiment ◽  
Fixed Target Experiment

scholarly journals KANE-PUMPLIN-REPKO FACTORIZATION: ITS APPLICATION TO PRECISION MEASUREMENTS OF TRANSVERSE SPIN ASYMMETRIES AND TO THE STUDY OF TMD EVOLUTION

2014 ◽  
Vol 25 ◽  
pp. 1460002 ◽  
Author(s):  
DENNIS SIVERS
Keyword(s):  
Transverse Momentum ◽  
Inelastic Scattering ◽  
Precision Measurements ◽  
Transverse Spin ◽  
Transverse Momentum Dependent ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Hadronic Structure ◽  
Single Spin Asymmetries ◽  
Fundamental Understanding

This article presents a summary of overlapping presentations by the author to the QCD Evolution 2013 Workshop (Jefferson Lab, May 6-10, 2013) and to the Opportunities for Polarized Physics at Fermilab workshop (Fermilab, May 20-22, 2013). It contains an introduction to the concept of Kane-Pumplin-Repko (KPR) factorization and describes how this concept can be used in the analysis of high precision measurements of parity-conserving transverse single-spin asymmetries. The discussion demonstrates that such measurements can not only probe directly for specific mechanisms that enhance our fundamental understanding of nonperturbative QCD dynamics but, because transverse spin asymmetries are unambiguously parameterized by a spin-directed momentum shift, 〈δkTN (x, μ2)〉 such measurements can also be used to calibrate other phenomenological applications of transverse momentum dependent distributions (TMDs) and of TMD evolution. The calibration supplied by these measurements can thus enable the use of TMD factorization for the exploration of a broad range of other aspects of hadronic structure. KPR factorization ensures that 〈δkTN (x, μ2)〉 remains invariant under TMD evolution and this invariance can be used in the precision comparison of transverse single-spin asymmetries in the Drell-Yan process with those in Semi-inclusive deep inelastic scattering.

QCD EVOLUTION FOR TRANSVERSE MOMENTUM DEPENDENT OBSERVABLES

2014 ◽  
Vol 25 ◽  
pp. 1460008
Author(s):  
PENG SUN ◽  
FENG YUAN
Keyword(s):  
Transverse Momentum ◽  
Inelastic Scattering ◽  
Deep Inelastic Scattering ◽  
Cross Sections ◽  
Lepton Pair ◽  
Transverse Spin ◽  
Transverse Momentum Dependent ◽  
Spin Asymmetries ◽  
Hadronic Physics

In this talk, we presented our recent studies of the QCD evolution effects on the transverse momentum dependent observables in semi-inclusive deep inelastic scattering and Drell-Yan lepton pair productions. The evolution is first tested for the spin average cross sections, and then applied to the Sivers single transverse spin asymmetries. The latter are among the important topics in hadronic physics research in recent years.

scholarly journals Physics perspectives with AFTER@LHC (A Fixed Target ExpeRiment at LHC)

2018 ◽  
Vol 171 ◽  
pp. 10001 ◽  
Author(s):  
L. Massacrier ◽  
M. Anselmino ◽  
R. Arnaldi ◽  
S.J. Brodsky ◽  
V. Chambert ◽  
...  
Keyword(s):  
Center Of Mass ◽  
Gluon Plasma ◽  
Fixed Target ◽  
Target Mode ◽  
Open Questions ◽  
Energy Domain ◽  
Target Experiment ◽  
One Year ◽  
Selection Of ◽  
Fixed Target Experiment

AFTER@LHC is an ambitious fixed-target project in order to address open questions in the domain of proton and neutron spins, Quark Gluon Plasma and high-x physics, at the highest energy ever reached in the fixed-target mode. Indeed, thanks to the highly energetic 7 TeV proton and 2.76 A.TeV lead LHC beams, center-of-mass energies as large as [see formula in PDF] = 115 GeV in pp/pA and [see formula in PDF] = 72 GeV in AA can be reached, corresponding to an uncharted energy domain between SPS and RHIC. We report two main ways of performing fixed-target collisions at the LHC, both allowing for the usage of one of the existing LHC experiments. In these proceedings, after discussing the projected luminosities considered for one year of data taking at the LHC, we will present a selection of projections for light and heavy-flavour production.

scholarly journals GENERALIZED UNIVERSALITY FOR TMD DISTRIBUTION FUNCTIONS

2012 ◽  
Vol 20 ◽  
pp. 66-74 ◽  
Author(s):  
M. G. A. BUFFING ◽  
P. J. MULDERS
Keyword(s):  
Transverse Momentum ◽  
Parton Distribution ◽  
Azimuthal Angle ◽  
High Energy ◽  
Distribution Functions ◽  
Transverse Spin ◽  
Parton Distribution Functions ◽  
Transverse Momentum Dependent ◽  
Spin Asymmetries ◽  
Azimuthal Asymmetries

Azimuthal asymmetries in high-energy processes, most pronounced showing up in combination with single or double (transverse) spin asymmetries, can be understood with the help of transverse momentum dependent (TMD) parton distribution and fragmentation functions. These appear in correlators containing expectation values of quark and gluon operators. TMDs allow access to new operators as compared to collinear (transverse momentum integrated) correlators. These operators include nontrivial process dependent Wilson lines breaking universality for TMDs. Making an angular decomposition in the azimuthal angle, we define a set of universal TMDs of definite rank, which appear with process dependent gluonic pole factors in a way similar to the sign of T-odd parton distribution functions in deep inelastic scattering or the Drell-Yan process. In particular, we show that for a spin 1/2 quark target there are three pretzelocity functions.

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