Reggie Bain
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
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Reggie Bain has a total of 6 co-authors. Here are the top co-authors by number of shared publications:
- Thomas Mehen
Duke University
6 shared publications - Yiannis Makris
Los Alamos National Laboratory
5 shared publications - Adam K. Leibovich
University of Pittsburgh
4 shared publications - Lin Dai
University of Pittsburgh
4 shared publications - Andrew Hornig
Theoretical Division T-2, Los Alamos National Laboratory, Los Alamos, U.S.A.
2 shared publications Yiannis Makris
Department of Physics Duke University Science Dr. Box 90305 27708 Durham NC USA
1 shared publication
Latest Publications
- Open Access
- 18 July 2017
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 119 (3) , 032002
NRQCD Confronts LHCb Data on Quarkonium Production within Jets
We analyze the recent LHCb measurement of the distribution of the fraction of the transverse momentum, , carried by the within a jet. LHCb data are compared with analytic calculations using the fragmenting jet function (FJF) formalism for studying in jets. Logarithms in the FJFs are resummed using Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution. We also convolve hard QCD partonic cross sections, showered with pythia, with leading order nonrelativistic quantum chromodynamics (NRQCD) fragmentation functions and obtain consistent results. Both approaches use madgraph to calculate the hard process that creates the jet initiating parton. These calculations give reasonable agreement with the distribution that was shown to be poorly described by default pythia simulations in the LHCb paper. We compare our predictions for the distribution using various extractions of nonperturbative NRQCD long-distance matrix elements (LDMEs) in the literature. NRQCD calculations agree with LHCb data better than default pythia regardless of which fit to the LDMEs is used. LDMEs from fits that focus exclusively on high transverse momentum data from colliders are in good agreement with the LHCb measurement.- 18 July 2017
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 119 (3) , 032002
Open AccessNRQCD Confronts LHCb Data on Quarkonium Production within Jets
We analyze the recent LHCb measurement of the distribution of the fraction of the transverse momentum, , carried by the within a jet. LHCb data are compared with analytic calculations using the fragmenting jet function (FJF) formalism for studying in jets. Logarithms in the FJFs are resummed using Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution. We also convolve hard QCD partonic cross sections, showered with pythia, with leading order nonrelativistic quantum chromodynamics (NRQCD) fragmentation functions and obtain consistent results. Both approaches use madgraph to calculate the hard process that creates the jet initiating parton. These calculations give reasonable agreement with the distribution that was shown to be poorly described by default pythia simulations in the LHCb paper. We compare our predictions for the distribution using various extractions of nonperturbative NRQCD long-distance matrix elements (LDMEs) in the literature. NRQCD calculations agree with LHCb data better than default pythia regardless of which fit to the LDMEs is used. LDMEs from fits that focus exclusively on high transverse momentum data from colliders are in good agreement with the LHCb measurement. - Open Access
NRQCD Confronts LHCb Data on Quarkonium Production within Jets
We analyze the recent LHCb measurement of the distribution of the fraction of the transverse momentum, $z(J/\psi)$, carried by the $J/\psi$ within a jet. LHCb data is compared to analytic calculations using the fragmenting jet function (FJF) formalism for studying $J/\psi$ in jets. Logarithms in the FJFs are resummed using DGLAP evolution. We also convolve hard QCD partonic cross sections, showered with PYTHIA, with leading order Non Relativistic Quantum Chromodynamics (NRQCD) fragmentation functions and obtain consistent results. Both approaches use Madgraph to calculate the hard process that creates the jet initiating parton. These calculations give reasonable agreement with the $z(J/\psi)$ distribution that was shown to be poorly described by default PYTHIA simulations in the LHCb paper. We compare our predictions for the $J/\psi$ distribution using various extractions of nonperturbative NRQCD long-distance matrix elements (LDMEs) in the literature. NRQCD calculations agree with LHCb data better than default PYTHIA regardless of which fit to the LDMEs is used. LDMEs from fits that focus exclusively on high transverse momentum data from colliders are in good agreement with the LHCb measurement.Open AccessNRQCD Confronts LHCb Data on Quarkonium Production within Jets
We analyze the recent LHCb measurement of the distribution of the fraction of the transverse momentum, $z(J/\psi)$, carried by the $J/\psi$ within a jet. LHCb data is compared to analytic calculations using the fragmenting jet function (FJF) formalism for studying $J/\psi$ in jets. Logarithms in the FJFs are resummed using DGLAP evolution. We also convolve hard QCD partonic cross sections, showered with PYTHIA, with leading order Non Relativistic Quantum Chromodynamics (NRQCD) fragmentation functions and obtain consistent results. Both approaches use Madgraph to calculate the hard process that creates the jet initiating parton. These calculations give reasonable agreement with the $z(J/\psi)$ distribution that was shown to be poorly described by default PYTHIA simulations in the LHCb paper. We compare our predictions for the $J/\psi$ distribution using various extractions of nonperturbative NRQCD long-distance matrix elements (LDMEs) in the literature. NRQCD calculations agree with LHCb data better than default PYTHIA regardless of which fit to the LDMEs is used. LDMEs from fits that focus exclusively on high transverse momentum data from colliders are in good agreement with the LHCb measurement. - Open Access
Transverse Momentum Dependent Fragmenting Jet Functions with Applications to Quarkonium Production
We introduce the transverse momentum dependent fragmenting jet function (TMDFJF), which appears in factorization theorems for cross sections for jets with an identified hadron. These are functions of $z$, the hadron's longitudinal momentum fraction, and transverse momentum, $\boldsymbol{\mathrm{p}}_{\perp}$, relative to the jet axis. In the framework of Soft-Collinear Effective Theory (SCET) we derive the TMDFJF from both a factorized SCET cross section and the TMD fragmentation function defined in the literature. The TMDFJFs are factorized into distinct collinear and soft-collinear modes by matching onto SCET$_+$. As TMD calculations contain rapidity divergences, both the renormalization group (RG) and rapidity renormalization group (RRG) must be used to provide resummed calculations with next-to-leading-logarithm prime (NLL') accuracy. We apply our formalism to the production of $J/\psi$ within jets initiated by gluons. In this case the TMDFJF can be calculated in terms of NRQCD (Non-relativistic quantum chromodynamics) fragmentation functions. We find that when the $J/\psi$ carries a significant fraction of the jet energy, the $p_T$ and $z$ distributions differ for different NRQCD production mechanisms. Another observable with discriminating power is the average angle that the $J/\psi$ makes with the jet axis.Open AccessTransverse Momentum Dependent Fragmenting Jet Functions with Applications to Quarkonium Production
We introduce the transverse momentum dependent fragmenting jet function (TMDFJF), which appears in factorization theorems for cross sections for jets with an identified hadron. These are functions of $z$, the hadron's longitudinal momentum fraction, and transverse momentum, $\boldsymbol{\mathrm{p}}_{\perp}$, relative to the jet axis. In the framework of Soft-Collinear Effective Theory (SCET) we derive the TMDFJF from both a factorized SCET cross section and the TMD fragmentation function defined in the literature. The TMDFJFs are factorized into distinct collinear and soft-collinear modes by matching onto SCET$_+$. As TMD calculations contain rapidity divergences, both the renormalization group (RG) and rapidity renormalization group (RRG) must be used to provide resummed calculations with next-to-leading-logarithm prime (NLL') accuracy. We apply our formalism to the production of $J/\psi$ within jets initiated by gluons. In this case the TMDFJF can be calculated in terms of NRQCD (Non-relativistic quantum chromodynamics) fragmentation functions. We find that when the $J/\psi$ carries a significant fraction of the jet energy, the $p_T$ and $z$ distributions differ for different NRQCD production mechanisms. Another observable with discriminating power is the average angle that the $J/\psi$ makes with the jet axis. - Open Access
- 23 November 2016
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2016 (11) , 144
Transverse momentum dependent fragmenting jet functions with applications to quarkonium production
- 23 November 2016
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2016 (11) , 144
Open AccessTransverse momentum dependent fragmenting jet functions with applications to quarkonium production
- Open Access
- 21 June 2016
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2016 (6) , 1-28
Analytic and Monte Carlo studies of jets with heavy mesons and quarkonia
- 21 June 2016
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2016 (6) , 1-28
Open AccessAnalytic and Monte Carlo studies of jets with heavy mesons and quarkonia
- Open Access
Analytic and Monte Carlo Studies of Jets with Heavy Mesons and Quarkonia
We study jets with identified hadrons in which a family of jet-shape variables called angularities are measured, extending the concept of fragmenting jet functions (FJFs) to these observables. FJFs determine the fraction of energy, z, carried by an identified hadron in a jet with angularity, \tau_a. The FJFs are convolutions of fragmentation functions (FFs), evolved to the jet energy scale, with perturbatively calculable matching coefficients. Renormalization group equations are used to provide resummed calculations with next-to-leading logarithm prime (NLL') accuracy. We apply this formalism to two-jet events in e^+ e^- collisions with B mesons in the jets, and three-jet events in which a J/\psi is produced in the gluon jet. In the case of B mesons, we use a phenomenological FF extracted from e^+ e^- collisions at the Z^0 pole evaluated at the scale \mu = m_b. For events with J/\psi, the FF can be evaluated in terms of Non-Relativistic QCD (NRQCD) matrix elements at the scale \mu =2 m_c. The z and \tau_a distributions from our NLL' calculations are compared with predictions from monte carlo event generators. While we find consistency between the predictions for B mesons and the J/\psi distributions in \tau_a, we find the z distributions for J/\psi differ significantly. We describe an attempt to merge PYTHIA showers with NRQCD FFs that gives good agreement with NLL' calculations of the z distributions.
Open AccessAnalytic and Monte Carlo Studies of Jets with Heavy Mesons and Quarkonia
We study jets with identified hadrons in which a family of jet-shape variables called angularities are measured, extending the concept of fragmenting jet functions (FJFs) to these observables. FJFs determine the fraction of energy, z, carried by an identified hadron in a jet with angularity, \tau_a. The FJFs are convolutions of fragmentation functions (FFs), evolved to the jet energy scale, with perturbatively calculable matching coefficients. Renormalization group equations are used to provide resummed calculations with next-to-leading logarithm prime (NLL') accuracy. We apply this formalism to two-jet events in e^+ e^- collisions with B mesons in the jets, and three-jet events in which a J/\psi is produced in the gluon jet. In the case of B mesons, we use a phenomenological FF extracted from e^+ e^- collisions at the Z^0 pole evaluated at the scale \mu = m_b. For events with J/\psi, the FF can be evaluated in terms of Non-Relativistic QCD (NRQCD) matrix elements at the scale \mu =2 m_c. The z and \tau_a distributions from our NLL' calculations are compared with predictions from monte carlo event generators. While we find consistency between the predictions for B mesons and the J/\psi distributions in \tau_a, we find the z distributions for J/\psi differ significantly. We describe an attempt to merge PYTHIA showers with NRQCD FFs that gives good agreement with NLL' calculations of the z distributions.