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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
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DOE OSTI2011

Azimuthal asymmetries in single polarized proton-proton Drell-Yan processes

We study the azimuthal asymmetries in proton-proton Drell-Yan processes with one incident proton being transversely or longitudinally polarized. We consider particularly the asymmetries contributed by the leading-twist chiral-odd quark distributions. We analyze the asymmetries with sin(2{phi}+{phi}{sub S}) and sin(2{phi}-{phi}{sub S}) modulations in transverse single polarized p{sup {up_arrow}p} Drell-Yan and sin2{phi} asymmetries in longitudinal single polarized p{sup {yields}p} Drell-Yan at the Relativistic Heavy Ion Collider, the Japan Proton Accelerator Research Complex, E906 (Fermi Lab), and the Nuclotron-based Ion Collider Facility (Joint Institute for Nuclear Research). We show that the measurements of the asymmetries in those facilities can provide valuable information of the chiral-odd structure of the nucleon both in the valence and sea regions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Exotic seesaw-motivated heavy leptons at the LHC

We study the LHC potential for discovering TeV-scale SU(2){sub L} 5-plet fermions introduced recently to explain small neutrino masses. We show that the Drell-Yan production and the decays of new exotic {Sigma} leptons are testable at the LHC. Their production is abundant due to nontrivial electroweak gauge charges. For 1 fb{sup -1} of integrated luminosity at the present LHC {radical}(s)=7 TeV, there can be 270 {Sigma}-{Sigma} pairs produced for M{sub {Sigma}=}400 GeV. Besides producing same-sign dilepton events, they could lead, due to a chosen small mixing between heavy and light leptons, to {approx}10 golden decays {Sigma}{sup +++}({Sigma}{sup +++}){yields}W{sup {+-}}W{sup {+-}}l{sup {+-}} with a specific decay signature.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

QCD Resummation for Single Spin Asymmetries

We study the transverse momentum dependent factorization for single spin asymmetries in Drell-Yan and semi-inclusive deep inelastic scattering processes at one-loop order. The next-to-leading order hard factors are calculated in the Ji-Ma-Yuan factorization scheme. We further derive the QCD resummation formalisms for these observables following the Collins-Soper-Sterman method. The results are expressed in terms of the collinear correlation functions from initial and/or final state hadrons coupled with the Sudakov form factor containing all order soft-gluon resummation effects. The scheme-independent coefficients are calculated up to one-loop order.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

COMPASS-II (Physics of Particles and Nuclei, v. 44(6))

On December 1st 2010 the proposal of the COMPASS-II Experiment [1] has been approved by the CERN Research Board. After almost ten years of important results achieved by the COMPASS Collaboration in both nucleon spin physics, with the use of muon beam, and hadron spectroscopy, using hadron beams, this second phase offers now a unique chance to address in the very near future newly opened QCD-related challenges, at very moderate upgrade cost, thanks to the versatility of the COMPASS apparatus [2]. This implies mainly study of chiral perturbation theory (ChPT), by measuring the pion polarizability through Primakoff reaction; generalized parton distributions (GPDs), by measuring exclusive deeply virtual compton scattering (DVCS) and hard exclusive meson production (DVMP); transverse momentum dependent parton distributions (TMDs) in single-polarised pion-induced Drell-Yan muon production and in SIDIS on a liquid hydrogen target (in parallel to DVCS). An overview of the COMPASS-II proposal is presented here, with a main focus on the new upcoming investigation of the nucleon structure via the Drell-Yan and DVCS processes.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Drell-Yan studies in ppbar reactions at FAIR

The nucleonic structure is far to be completely understood. A transverse momentum dependent description of the nucleon structure is a crucial milestone for several forthcoming studies in a wide range of experimental scenarios. By mean of antiproton beams, eventually polarized, that will be available at the future FAIR facility with a beam momentum up to 15 GeV/ c, the non-perturbative region of the QCD could be accessed. One of the main goal of the forthcoming experiments at FAIR is the investigation of those Drell-Yan lepton pairs produced in proton-antiproton annihilations, taking advantage of the high expected luminosities. Drell-Yan studies are a unique tool to access the spin depending properties of the nucleon, and namely its transverse degrees of freedom. Transverse Momentum Dependent (TMD) Parton Distribution Functions (PDFs), in particular the Boer-Mulders, the Sivers and the Transversity distribution functions, could be widely investigated by mean of the corresponding experimental azimuthal asymmetries. In later stages of FAIR, single- and double-spin asymmetries could be investigated as well. The Drell-Yan physics program which could be accessed at FAIR will be discussed in details, with a particular focus on the PANDA experimental scenario.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

Polarised Drell-Yan measurements at COMPASS-II

The spin structure of the nucleon and its Parton Distribution Functions (PDFs) are important topics studied by the COMPASS experiment at CERN. So far, the transverse momentum dependent PDFs (TMD PDFs) of the proton and deuteron have been studied in Semi-Inclusive Deep Inelastic Scattering (SIDIS). The Drell-Yan (DY) process is a complementary way to access the TMD PDFs, using a transversely polarised target. Studying the angular distributions of dimuons from the DY events produced in the collisions of a π{sup −} beam with 190 GeV/c momentum off a transversely polarised proton target (NH{sub 3}) we are able to extract the azimuthal spin asymmetries, which are generated by 4 out of the 8 TMD PDFs needed to describe the nucleon structure at leading order QCD. The expected sign change in Sivers and Boer-Mulders functions when accessed from DY and SIDIS will be checked [1]. The opportunity to study, in the same experiment, the TMD PDFs from both SIDIS and DY processes is unique at COMPASS. The COMPASS II Proposal [2] was approved by CERN including one year for polarised DY measurements; the beginning of the DY data taking is scheduled for 2014. The feasibility of the measurement was proven by several beam tests performed so far.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

Singularities, boundary conditions and gauge link in the light cone gauge

In this work, we first review the issues on the singularities and the boundary conditions in light cone gauge and how to regularize them properly. Then we will further review how these singularities and the boundary conditions can result in the gauge link at the infinity in the light cone direction in the Drell-Yan process. Except for reviewing, we also have verified that the gauge link at the light cone infinity has no dependence on the path not only for the Abelian field but also for non-Abelian gauge field.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Search for long-lived, multi-charged particles in pp collisions at s =7 TeV using the ATLAS detector

CERN-LHC. Measurements of the upper limits of cross sections for the production of highly ionising, penetrating particles with electric charges, |q|, from 2e to 6e in proton-proton collisions at a centre-of-mass energy of 7 TeV. The data, collected during the 2011 running period, have an integrated luminosity of 4.4 fb-1. The observed upper limits are present together with the expected limits. Also shown are the rapidly falling cross sections from the Drell-Yan model.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Search for Contact Interactions in the Dimuon Channel in $pp$ Collisions at $\sqrt{s} = 7$ TeV at CMS

The standard model fails to explain the variety of observed quark and lepton avors and their masses suggesting that there might exist a more fundamental basis. If quarks and leptons are composite particles made up of more basic constituents, a new physics interaction in the form of a four-fermion contact interaction arises between them. Experimentally the signal is manifest as a deviation from the standard model prediction in the high-mass tail for the invariant mass distribution of the opposite-sign dimuon pairs. The Large Hadron Collider accelerator at the Center for European Nuclear Research is built to explore new physics possibilities from proton-proton collisions occurring at the world's highest center-of-mass energy. This thesis discusses in detail a search strategy for a new physics possibility based on a left-handed current model of contact interactions. Based on 5.3 fb -1 of 2011 data as collected by the Compact Muon Solenoid detector, exclusion lower limits at 95% con dence level are set on the compositeness energy scale , for both destructive and constructive interferences of the new physics with the standard model Drell-Yan process. These limits form the most stringent limits to date and exceed the current published limits signi cantly.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

A Future Polarized Drell-Yan Experiment at Fermilab

The topic is treated in a series of slides under the following headings: Motivation (Nucleon Spin Puzzle, Quark Orbital Momentum and the Sivers Function, Accessing Sivers via Polarized Drell-Yan (p+p↑ → μ + μ - )); Transition of Seaquest (E906 → E1039) (Building a Polarized proton Target, Status of Polarized Target); and Outlook. The nucleon spin puzzle: when the quark and gluon contributions to the proton spin are evaluated, nearly 50% of the measured spin is missing; lattice QCD calculations indicate as much as 50% may come from quark orbital angular momentum. Sea quarks should carry orbital angular momentum (O.A.M.). The E1039 Polarized Target Drell-Yan Experiment provides opportunity to study possible Sea Quark O.A.M. Data taking is expected to begin in the spring of 2017.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Search for heavy long-lived multi-charged particles in pp collisions at √s = 8 TeV using the ATLAS detector

A search for heavy long-lived multi-charged particles is performed using the ATLAS detector at the LHC. Data collected in 2012 at √s = 8 TeV from pp collisions corresponding to an integrated luminosity of 20.3 fb -1 are examined. Particles producing anomalously high ionisation, consistent with long-lived massive particles with electric charges from |q| = 2e to |q| = 6e are searched for. No signal candidate events are observed, and 95 % confidence level cross-section upper limits are interpreted as lower mass limits for a Drell–Yan production model. The mass limits range between 660 and 785 GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

The Partonic Structure of the Pion at Large-x

Unlike the proton, whose parton distributions have been extracted using abundant data, the pion has been relatively ignored. The pion, nevertheless, is a crucial part of the current understanding of the nucleon's parton distributions and of the binding of the nucleon into a nucleus. The pion's structure becomes more intriguing when its dual roles as a light quark-antiquark system and as QCD's Goldstone boson are considered. One source of data on the pion's structure is pion-induced Drell-Yan scattering. Two recent re-analyses of such data are discussed here.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Search for multiply charged Heavy Stable Charged Particles in data collected with the CMS detector

Several models of new physics yield particles that are massive, long-lived, and have an electric charge, Q, greater than that of the electron, e. A search for evidence of such particles was performed using 5.0 fb -1 and 18.8 fb -1 of proton-proton collision data collected at √s = 7 TeV and √s = 8 TeV, respectively, with the Compact Muon Solenoid detector at the Large Hadron Collider. The distinctive detector signatures of these particles are that they are slow-moving and highly ionizing. Ionization energy loss and time-of- flight measurements were made using the inner tracker and the muon system, respectively. The search is sensitive to 1e ≤ |Q| ≤ 8e. Data were found to be consistent with standard model expectations and upper limits on the production cross section of these particles were computed using a Drell-Yan-like production model. Masses below 517, 687, 752, 791, 798, 778, 753, and 724 GeV are excluded for |Q| = 1e, 2e, 3e, 4e, 5e, 6e, 7e, and 8e, respectively.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

A polarized Drell-Yan experiment to probe the dynamics of the nucleon sea

In QCD, nucleon spin comes from the sum of the quark spin, gluon spin, and the quark and gluon orbital angular momentum, but how these different components contribute and the interplay among them is not yet understood. For instance, sea quark orbital contribution remains largely unexplored. Measurements of the Sivers function for the sea quarks will provide a probe of the sea quark orbital contribution. The upcoming E1039 experiment at Fermilab will measure the Sivers asymmetry of the sea quarks via the Drell-Yan process using a 120 GeV unpolarized proton beam directed a transversely polarized ammonia target. We report on the status and plans of the E1039 polarized Drell-Yan experiment.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗