Abstract
We discuss the role of intrinsic charm (IC) in the nucleon for forward production of c-quark (or \( \overline{c} \)-antiquark) in proton-proton collisions for low and high energies. The calculations are performed in collinear-factorization approach with on-shell partons, kT-factorization approach with off-shell partons as well as in a hybrid approach using collinear charm distributions and unintegrated (transverse momentum dependent) gluon distributions. For the collinear-factorization approach we use matrix elements for both massless and massive charm quarks/antiquarks. The distributions in rapidity and transverse momentum of charm quark/antiquark are shown for a few different models of IC. Forward charm production is dominated by gc-fusion processes. The IC contribution dominates over the standard pQCD (extrinsic) gg-fusion mechanism of \( c\overline{c} \)-pair production at large rapidities or Feynman-xF. We perform similar calculations within leading-order and next-to-leading order kT-factorization approach. The kT-factorization approach leads to much larger cross sections than the LO collinear approach. At high energies and large rapidities of c-quark or \( \overline{c} \)-antiquark one tests gluon distributions at extremely small x. The IC contribution has important consequences for high-energy neutrino production in the Ice-Cube experiment and can be, to some extent, tested at the LHC by the SHIP and FASER experiments by studies of the ντ neutrino production.
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S.J. Brodsky, P. Hoyer, C. Peterson and N. Sakai, The Intrinsic Charm of the Proton, Phys. Lett. B 93 (1980) 451 [INSPIRE].
V.D. Barger, F. Halzen and W.-Y. Keung, The Central and Diffractive Components of Charm Production, Phys. Rev. D 25 (1982) 112 [INSPIRE].
R. Vogt and S.J. Brodsky, QCD and intrinsic heavy quark predictions for leading charm and beauty hadroproduction, Nucl. Phys. B 438 (1995) 261 [hep-ph/9405236] [INSPIRE].
F.S. Navarra, M. Nielsen, C.A.A. Nunes and M. Teixeira, On the intrinsic charm component of the nucleon, Phys. Rev. D 54 (1996) 842 [hep-ph/9504388] [INSPIRE].
W. Melnitchouk and A.W. Thomas, HERA anomaly and hard charm in the nucleon, Phys. Lett. B 414 (1997) 134 [hep-ph/9707387] [INSPIRE].
F.M. Steffens, W. Melnitchouk and A.W. Thomas, Charm in the nucleon, Eur. Phys. J. C 11 (1999) 673 [hep-ph/9903441] [INSPIRE].
F. Carvalho, F.O. Duraes, F.S. Navarra and M. Nielsen, Does the D+ /D− production asymmetry decrease at large xF?, Phys. Rev. Lett. 86 (2001) 5434 [hep-ph/0009276] [INSPIRE].
T.J. Hobbs, J.T. Londergan and W. Melnitchouk, Phenomenology of nonperturbative charm in the nucleon, Phys. Rev. D 89 (2014) 074008 [arXiv:1311.1578] [INSPIRE].
R.S. Sufian et al., Constraints on charm-anticharm asymmetry in the nucleon from lattice QCD, Phys. Lett. B 808 (2020) 135633 [arXiv:2003.01078] [INSPIRE].
P.-H. Beauchemin, V.A. Bednyakov, G.I. Lykasov and Y.Y. Stepanenko, Search for intrinsic charm in vector boson production accompanied by heavy flavor jets, Phys. Rev. D 92 (2015) 034014 [arXiv:1410.2616] [INSPIRE].
S. Rostami, A. Khorramian, A. Aleedaneshvar and M. Goharipour, The impact of the intrinsic charm quark content of a proton on the differential γ + c cross section, J. Phys. G 43 (2016) 055001 [arXiv:1510.08421] [INSPIRE].
A.V. Lipatov, G.I. Lykasov, Y.Y. Stepanenko and V.A. Bednyakov, Probing proton intrinsic charm in photon or Z boson production accompanied by heavy jets at the LHC, Phys. Rev. D 94 (2016) 053011 [arXiv:1606.04882] [INSPIRE].
V.A. Bednyakov et al., Constraints on the intrinsic charm content of the proton from recent ATLAS data, Eur. Phys. J. C 79 (2019) 92 [arXiv:1712.09096] [INSPIRE].
S.J. Brodsky, A. Kusina, F. Lyonnet, I. Schienbein, H. Spiesberger and R. Vogt, A review of the intrinsic heavy quark content of the nucleon, Adv. High Energy Phys. 2015 (2015) 231547 [arXiv:1504.06287] [INSPIRE].
NNPDF collaboration, Parton distributions for the LHC Run II, JHEP 04 (2015) 040 [arXiv:1410.8849] [INSPIRE].
T.-J. Hou et al., CT14 Intrinsic Charm Parton Distribution Functions from CTEQ-TEA Global Analysis, JHEP 02 (2018) 059 [arXiv:1707.00657] [INSPIRE].
S.J. Brodsky, G.I. Lykasov, A.V. Lipatov and J. Smiesko, Novel Heavy-Quark Physics Phenomena, Prog. Part. Nucl. Phys. 114 (2020) 103802 [arXiv:2006.09443] [INSPIRE].
R. Enberg, M.H. Reno and I. Sarcevic, Prompt neutrino fluxes from atmospheric charm, Phys. Rev. D 78 (2008) 043005 [arXiv:0806.0418] [INSPIRE].
R. Laha and S.J. Brodsky, IceCube can constrain the intrinsic charm of the proton, Phys. Rev. D 96 (2017) 123002 [arXiv:1607.08240] [INSPIRE].
A.V. Giannini, V.P. Gonçalves and F.S. Navarra, Intrinsic charm contribution to the prompt atmospheric neutrino flux, Phys. Rev. D 98 (2018) 014012 [arXiv:1803.01728] [INSPIRE].
R. Maciuła and A. Szczurek, D meson production asymmetry, unfavored fragmentation, and consequences for prompt atmospheric neutrino production, Phys. Rev. D 97 (2018) 074001 [arXiv:1711.08616] [INSPIRE].
W. Bai, M. Diwan, M.V. Garzelli, Y.S. Jeong and M.H. Reno, Far-forward neutrinos at the Large Hadron Collider, JHEP 06 (2020) 032 [arXiv:2002.03012] [INSPIRE].
W. Bai and M.H. Reno, Prompt neutrinos and intrinsic charm at SHiP, JHEP 02 (2019) 077 [arXiv:1807.02746] [INSPIRE].
LHCb collaboration, First Measurement of Charm Production in its Fixed-Target Configuration at the LHC, Phys. Rev. Lett. 122 (2019) 132002 [arXiv:1810.07907] [INSPIRE].
R. Maciuła, QCD predictions for open charm meson production at the LHCb in a fixed-target experiment, Phys. Rev. D 102 (2020) 014028 [arXiv:2003.05702] [INSPIRE].
V.P. Goncalves and F.S. Navarra, Looking for intrinsic charm in the forward region at BNL RHIC and CERN LHC, Nucl. Phys. A 842 (2010) 59 [arXiv:0805.0810] [INSPIRE].
F. Carvalho, A.V. Giannini, V.P. Goncalves and F.S. Navarra, D-meson production at very forward rapidities: estimating the intrinsic charm contribution, Phys. Rev. D 96 (2017) 094002 [arXiv:1701.08451] [INSPIRE].
A. Edin and G. Ingelman, A Model for the parton distributions in hadrons, Phys. Lett. B 432 (1998) 402 [hep-ph/9803496] [INSPIRE].
M. Gluck, E. Reya and A. Vogt, Dynamical parton distributions of the proton and small x physics, Z. Phys. C 67 (1995) 433 [INSPIRE].
J. Pumplin, H.L. Lai and W.K. Tung, The Charm Parton Content of the Nucleon, Phys. Rev. D 75 (2007) 054029 [hep-ph/0701220] [INSPIRE].
J.C. Collins, D.E. Soper and G.F. Sterman, Factorization of Hard Processes in QCD, Adv. Ser. Direct. High Energy Phys. 5 (1989) 1 [hep-ph/0409313] [INSPIRE].
NNPDF collaboration, A Determination of the Charm Content of the Proton, Eur. Phys. J. C 76 (2016) 647 [arXiv:1605.06515] [INSPIRE].
L.A. Harland-Lang, A.D. Martin, P. Motylinski and R.S. Thorne, Parton distributions in the LHC era: MMHT 2014 PDFs, Eur. Phys. J. C 75 (2015) 204 [arXiv:1412.3989] [INSPIRE].
P. Jimenez-Delgado and E. Reya, Delineating parton distributions and the strong coupling, Phys. Rev. D 89 (2014) 074049 [arXiv:1403.1852] [INSPIRE].
A. van Hameren, KaTie: For parton-level event generation with kT-dependent initial states, Comput. Phys. Commun. 224 (2018) 371 [arXiv:1611.00680] [INSPIRE].
T. Sjöstrand et al., An introduction to PYTHIA 8.2, Comput. Phys. Commun. 191 (2015) 159 [arXiv:1410.3012] [INSPIRE].
B.A. Kniehl, G. Kramer, I. Schienbein and H. Spiesberger, Inclusive Charmed-Meson Production at the CERN LHC, Eur. Phys. J. C 72 (2012) 2082 [arXiv:1202.0439] [INSPIRE].
M. Deak, F. Hautmann, H. Jung and K. Kutak, Forward Jet Production at the Large Hadron Collider, JHEP 09 (2009) 121 [arXiv:0908.0538] [INSPIRE].
K. Kutak and S. Sapeta, Gluon saturation in dijet production in p-Pb collisions at Large Hadron Collider, Phys. Rev. D 86 (2012) 094043 [arXiv:1205.5035] [INSPIRE].
P. Kotko, K. Kutak, C. Marquet, E. Petreska, S. Sapeta and A. van Hameren, Improved TMD factorization for forward dijet production in dilute-dense hadronic collisions, JHEP 09 (2015) 106 [arXiv:1503.03421] [INSPIRE].
F. Hautmann and H. Jung, Transverse momentum dependent gluon density from DIS precision data, Nucl. Phys. B 883 (2014) 1 [arXiv:1312.7875] [INSPIRE].
K. Kutak, Hard scale dependent gluon density, saturation and forward-forward dijet production at the LHC, Phys. Rev. D 91 (2015) 034021 [arXiv:1409.3822] [INSPIRE].
A. Bermudez Martinez et al., Collinear and TMD parton densities from fits to precision DIS measurements in the parton branching method, Phys. Rev. D 99 (2019) 074008 [arXiv:1804.11152] [INSPIRE].
G. Watt, A.D. Martin and M.G. Ryskin, Unintegrated parton distributions and inclusive jet production at HERA, Eur. Phys. J. C 31 (2003) 73 [hep-ph/0306169] [INSPIRE].
A. van Hameren, private communication.
R. Maciuła and A. Szczurek, Consistent treatment of charm production in higher-orders at tree-level within kT-factorization approach, Phys. Rev. D 100 (2019) 054001 [arXiv:1905.06697] [INSPIRE].
A.V. Lipatov, M.A. Malyshev and H. Jung, Relation between the parton branching approach and Catani-Ciafaloni-Fiorani-Marchesini evolution, Phys. Rev. D 101 (2020) 034022 [arXiv:1910.11224] [INSPIRE].
S. Catani, M. Ciafaloni and F. Hautmann, Gluon contributions to small x heavy flavor production, Phys. Lett. B 242 (1990) 97 [INSPIRE].
S. Catani, M. Ciafaloni and F. Hautmann, High-energy factorization and small x heavy flavor production, Nucl. Phys. B 366 (1991) 135 [INSPIRE].
S. Catani, M. Ciafaloni and F. Hautmann, High-energy factorization in QCD and minimal subtraction scheme, Phys. Lett. B 307 (1993) 147 [INSPIRE].
J.C. Collins and R. Ellis, Heavy quark production in very high-energy hadron collisions, Nucl. Phys. B 360 (1991) 3 [INSPIRE].
L.V. Gribov, E.M. Levin and M.G. Ryskin, Semihard Processes in QCD, Phys. Rept. 100 (1983) 1 [INSPIRE].
E.M. Levin, M.G. Ryskin, Y. Shabelski and A.G. Shuvaev, Heavy quark production in semihard nucleon interactions, Sov. J. Nucl. Phys. 53 (1991) 657 [INSPIRE].
M.A. Nefedov, V.A. Saleev and A.V. Shipilova, Dijet azimuthal decorrelations at the LHC in the parton Reggeization approach, Phys. Rev. D 87 (2013) 094030 [arXiv:1304.3549] [INSPIRE].
M. Czech and A. Szczurek, Unintegrated parton distributions and pion production in pp collisions at RHIC’s energies, J. Phys. G 32 (2006) 1253 [nucl-th/0510007] [INSPIRE].
I. Babiarz, R. Pasechnik, W. Schäfer and A. Szczurek, Prompt hadroproduction of ηc (1S, 2S) in the kT-factorization approach, JHEP 02 (2020) 037 [arXiv:1911.03403] [INSPIRE].
I. Babiarz, R. Pasechnik, W. Schäfer and A. Szczurek, Hadroproduction of scalar P –wave quarkonia in the light-front kT-factorization approach, JHEP 06 (2020) 101 [arXiv:2002.09352] [INSPIRE].
A. Szczurek, A new parton fragmentation procedure for heavy hadron production in proton-proton collisions, arXiv:2006.12918 [INSPIRE].
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Maciuła, R., Szczurek, A. Intrinsic charm in the nucleon and charm production at large rapidities in collinear, hybrid and kT-factorization approaches. J. High Energ. Phys. 2020, 135 (2020). https://doi.org/10.1007/JHEP10(2020)135
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DOI: https://doi.org/10.1007/JHEP10(2020)135