Associated production of prompt photons and heavy quarks in off-shell gluon–gluon fusion

Baranov, S. P.; Lipatov, A. V.; Zotov, N.P.

doi:10.1140/epjc/s10052-008-0654-y

Cited by 23 publications

(20 citation statements)

References 55 publications

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“…The calculation utilizes CTEQ6.6M parton distribution functions [13]. The scale dependence is evaluated by varying the renormalization, µ r , factorization, µ f , and fragmentation, µ F , scales, assumed to be the same, from the default value p The predictions based on a k T -factorization approach [14] include O(αα 2 s ) off-shell amplitudes of gluon-gluon fusion and quark-(anti)quark interaction subprocesses, and the k T -dependent (i.e., unintegrated) parton distributions, where k T denotes the transverse momentum of the parton. The nonvanishing transverse momentum of the colliding partons leads to a broadening of the photon transversemomentum distribution.…”

mentioning

confidence: 99%

Measurement of the Cross Section for Direct-Photon Production in Association with a Heavy Quark inpp¯Collisions ats=1.96
Aaltonen¹,
Amerio²,
Amidei³
et al. 2013
Phys. Rev. Lett.
29
1
33
0
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We report on a measurement of the cross section for direct-photon production in association with a heavy quark using the full data set of √ s = 1.96 TeV proton-antiproton collisions corresponding to 9.1 fb −1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron. The measurements are performed as a function of the photon transverse momentum, covering photon transverse momentum between 30 and 300 GeV, photon rapidities |y γ | < 1.0, heavy-quark-jet transverse momentum p jet T > 20 GeV, and jet rapidities |y jet | < 1.5. The results are compared with several theoretical predictions.PACS numbers: 12.38. Qk, 13.85.Qk, 13.87.Ce The study of direct-photon (γ) production in association with a heavy quark Q (b or c) in hadronic collisions provides valuable information on the probability distributions of partons inside the initialstate hadrons. At photon transverse energies E γ T[1] smaller than 100 GeV, such events are produced predominantly by the Compton scattering process gQ → γQ, while at higher energies the dominant process is quark-antiquark annihilation with gluon (g) splitting to heavy quarks qq → γg → γQQ [2]. It is conventional to assume that the charm (c) and bottom (b) quarks in the proton arise only from gluon splitting. However, there are other models that allow the existence of intrinsic heavy quarks in the proton [3]. A cross-section measurement of γ + Q + X (X can be any final-state particle) production provides information on the heavy-quark and gluon parton distribution functions (PDFs) and on the rate of final-state gluon splitting to heavy quarks.The Collider Detector at Fermilab (CDF) Collaboration studied the process pp → γ + b + X at √ s = 1.96 TeV, for photons in the range 20 < E γ T < 70 GeV [4]. The measured cross section agreed well with a prediction based on a perturbative quantum chromodynamics (pQCD) expansion [2] at next-toleading order (NLO) in the strong coupling constant α s . The D0 Collaboration measured the cross section for photons in association with heavy-flavor jets using data collected at √ s = 1.96 TeV, covering the range 30 < E γ T < 300 GeV [5]. The results disagreed with the NLO pQCD prediction for both bottom jets and charm jets in the region E γ T > ∼ 70 GeV. In this Letter, we present the updated CDF measurements of the cross sections of photon with heavy-flavor jets, using the full data set from 9.1 4 fb −1 of integrated luminosity collected by the CDF II detector, exploring E γ T up to 300 GeV with improved techniques. The CDF II detector [6] has a cylindrical geometry with approximate forwardbackward and azimuthal symmetry [1]. It contains a tracking system consisting of silicon microstrip detectors and a cylindrical open-cell drift chamber immersed in a 1.4 T magnetic field parallel to the beam axis. The silicon subsystem is used for reconstructing charged-particle trajectories (tracks) and heavyflavor-decay vertices displaced from the primary interaction point. Electromagnetic (EM) and hadronic calorimeters surrounding the tracking sy...

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mentioning

confidence: 99%

Measurement of the Cross Section for Direct-Photon Production in Association with a Heavy Quark inpp¯Collisions ats=1.96
Aaltonen¹,
Amerio²,
Amidei³
et al. 2013
Phys. Rev. Lett.
29
1
33
0
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“…A good description of the results of the D0 and CDF collaborations was achieved. Also in [7] the process of the prompt photon production with associated heavy (c, b) quarks was investigated and a reasonable agreement of the experimental data with the theoretical results was obtained. Here we expand the analysis to the LHC energies.…”

Section: Pos(qfthep2011)028mentioning

confidence: 52%

Prompt photon production in the kt-factorization approach at modern colliders

Malyshev¹,

Lipatov²,

Zotov³

2012

Proceedings of the XXth International Workshop High Energy Physics and Quantum Field Theory — PoS(QFTHEP2011)

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We present the results of the numerical calculations of prompt photon and Drell-Yan lepton pair production at Tevatron and LHC in the framework of the k T -factorization approach. Our predictions are compared with the D0, CDF, CMS and ATLAS experimental data. The XXth International Workshop High Energy Physics and Quantum Field Theory September 24 -October 1, 2011Sochi, Russia * Speaker.c Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.http://pos.sissa.it/ PoS(QFTHEP2011)028Prompt photon and Drell-Yan lepton pair production in the k T -factorization approach M. A. Malyshev Our study is motivated by recent measurements of the inclusive prompt photon and Drell-Yan lepton pair production performed by the CMS and ATLAS collaborations at LHC [1 -3], taken at √ s = 7 TeV. Previously the k T -factorization approach was used for the prompt photon production at Tevatron [4 -6]. A good description of the results of the D0 and CDF collaborations was achieved. Also in [7] the process of the prompt photon production with associated heavy (c, b) quarks was investigated and a reasonable agreement of the experimental data with the theoretical results was obtained. Here we expand the analysis to the LHC energies.According to the k T -factorization theorem, to calculate the cross section of the prompt photon or Drell-Yan lepton pair production one should convolute the off-shell partonic cross sections with the relevant unintegrated quark and/or gluon distributions in a proton:) is the relevant partonic cross section. The initial off-shell partons have fractions x 1 and x 2 of initial protons longitudinal momenta and non-zero transverse momenta k 1T and k 2T .Concerning the unintegrated parton distributions we use two different sets. First is the KMR set [8,9]. The KMR approach represents an approximate treatment of the parton evolution mainly based on the DGLAP equation and incorpotating the BFKL effects at the last step of the parton ladder only, in the form of the properly defined Sudakov formfactors T q (k 2 T , µ 2 ) and T q (k 2 T , µ 2 ), including logarithmic loops. In this approach both gluons and quarks densities can be obtained.For prompt photon production we also use another set of unintegrated parton distributions, obtained as a numerical solution of the CCFM evolution equation [10], namely the CCFM A0 set. However, as a result of the solution we have only gluon distribution. In order to calculate the quarks distribution, we follow the scheme, proposed in [5,6]. The unintegrated quark distribution are presented aswhere f (v) q is the unintegrated valence quarks distribution and fq -the contributions of the sea quarks arising from the last and earlier steps of the parton evolution respectively. f (v) q (x, k 2 T , µ 2 ) was calculated in [11]. The contribution from the sea quarks coming from the last evolution step, f, can be taken into account with the gluon fusion subprocess, g * g * → γqq [6]. The contribution of the sea quarks coming fro...

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“…To estimate the contribution of the sea quarks coming from the earlier evolution steps we apply the procedure based on the specific properties of the KMR scheme. Modifying (3) in such a way [24] that only the first term is kept and the second term is omitted and keeping only the sea quark in first term, we remove the valence and f…”

Section: Tmentioning

confidence: 99%

Phenomenology of kT-factorization for inclusive top quark pair production at hadron colliders

Lipatov

Zotov

2011

Physics Letters B

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We investigate the inclusive top quark pair production in proton-proton and protonantiproton collisions at high energies in the framework of k T -factorization QCD approach. Our study is based on the off-shell partonic subprocesses g * g * → QQ and q * q * → QQ, where the transverse momentum of both incoming quarks and gluons are taken into account. The unintegrated parton densities in a proton are determined by the Kimber-Martin-Ryskin prescription as well as the CCFM evolution equation. The conservative error analisys is performed and comparison with the results of traditional NLO pQCD calculations is done. Our predictions agree well with the recent experimental data taken by the D0, CDF, CMS and ATLAS collaborations at the Tevatron and LHC energies. PACS number(s): 14.65.Ha, 12.38.-t 1

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Associated production of prompt photons and heavy quarks in off-shell gluon–gluon fusion

Cited by 23 publications

References 55 publications

Measurement of the Cross Section for Direct-Photon Production in Association with a Heavy Quark inpp¯Collisions ats=1.96
Aaltonen¹,
Amerio²,
Amidei³
et al. 2013
Phys. Rev. Lett.
29
1
33
0
View full text Add to dashboard Cite

Measurement of the Cross Section for Direct-Photon Production in Association with a Heavy Quark inpp¯Collisions ats=1.96
Aaltonen¹,
Amerio²,
Amidei³
et al. 2013
Phys. Rev. Lett.
29
1
33
0
View full text Add to dashboard Cite

Prompt photon production in the kt-factorization approach at modern colliders

Phenomenology of kT-factorization for inclusive top quark pair production at hadron colliders

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Associated production of prompt photons and heavy quarks in off-shell gluon–gluon fusion

Cited by 23 publications

References 55 publications

Measurement of the Cross Section for Direct-Photon Production in Association with a Heavy Quark inpp¯Collisions ats=1.96 Aaltonen1, Amerio2, Amidei3 et al. 2013Phys. Rev. Lett.291330View full textAdd to dashboardCite

Measurement of the Cross Section for Direct-Photon Production in Association with a Heavy Quark inpp¯Collisions ats=1.96 Aaltonen1, Amerio2, Amidei3 et al. 2013Phys. Rev. Lett.291330View full textAdd to dashboardCite

Prompt photon production in the kt-factorization approach at modern colliders

Phenomenology of kT-factorization for inclusive top quark pair production at hadron colliders

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Product

Resources

About

Measurement of the Cross Section for Direct-Photon Production in Association with a Heavy Quark inpp¯Collisions ats=1.96
Aaltonen¹,
Amerio²,
Amidei³
et al. 2013
Phys. Rev. Lett.
29
1
33
0
View full text Add to dashboard Cite

Measurement of the Cross Section for Direct-Photon Production in Association with a Heavy Quark inpp¯Collisions ats=1.96
Aaltonen¹,
Amerio²,
Amidei³
et al. 2013
Phys. Rev. Lett.
29
1
33
0
View full text Add to dashboard Cite