# Diffractive and non-diffractive wounded nucleons and final states in pA collisions

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## Abstract

We review the state-of-the-art of Glauber-inspired models for estimating the distribution of the number of participating nucleons in p*A* and *AA* collisions. We argue that there is room for improvement in these model when it comes to the treatment of diffractive excitation processes, and present a new simple Glauber-like model where these processes are better taken into account. We also suggest a new way of using the number of participating, or wounded, nucleons to extrapolate event characteristics from pp collisions, and hence get an estimate of basic hadronic final-state properties in p*A* collisions, which may be used to extract possible nuclear effects. The new method is inspired by the Fritiof model, but based on the full, semi-hard multiparton interaction model of Pythia8.

## Keywords

Heavy Ion Phenomenology QCD Phenomenology## Notes

### **Open Access**

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## References

- [1]A. Bzdak and V. Skokov,
*Decisive test of color coherence in proton-nucleus collisions at the LHC*,*Phys. Rev. Lett.***111**(2013) 182301 [arXiv:1307.6168] [INSPIRE].ADSCrossRefGoogle Scholar - [2]L. McLerran and M. Praszalowicz,
*Fluctuations and the rapidity dependence of charged particles spectra in fixed centrality bins in pA collisions*,*Annals Phys.***372**(2016) 215 [arXiv:1507.05976] [INSPIRE].ADSMathSciNetCrossRefGoogle Scholar - [3]R.J. Glauber,
*Cross-sections in deuterium at high-energies*,*Phys. Rev.***100**(1955) 242 [INSPIRE].ADSCrossRefGoogle Scholar - [4]M.L. Miller, K. Reygers, S.J. Sanders and P. Steinberg,
*Glauber modeling in high energy nuclear collisions*,*Ann. Rev. Nucl. Part. Sci.***57**(2007) 205 [nucl-ex/0701025] [INSPIRE]. - [5]CDF collaboration, F. Abe et al.,
*Measurement of pp single diffraction dissociation at*\( \sqrt{s}=546 \)*GeV and*1800*GeV*,*Phys. Rev.***D 50**(1994) 5535 [INSPIRE]. - [6]ATLAS collaboration,
*Rapidity gap cross sections measured with the ATLAS detector in pp collisions at*\( \sqrt{s}=7 \)*TeV*,*Eur. Phys. J.***C 72**(2012) 1926 [arXiv:1201.2808] [INSPIRE]. - [7]CMS collaboration,
*Measurement of diffraction dissociation cross sections in pp collisions at*\( \sqrt{s}=7 \)*TeV*,*Phys. Rev.***D 92**(2015) 012003 [arXiv:1503.08689] [INSPIRE]. - [8]V.N. Gribov,
*Glauber corrections and the interaction between high-energy hadrons and nuclei*,*Sov. Phys. JETP***29**(1969) 483 [*Zh. Eksp. Teor. Fiz.***56**(1969) 892] [INSPIRE]. - [9]G. Gustafson, L. L”onnblad, A. Ster and T. Cs”orgő,
*Total, inelastic and (quasi-)elastic cross sections of high energy pA and γA reactions with the dipole formalism*,*JHEP***10**(2015) 022 [arXiv:1506.09095] [INSPIRE]. - [10]H. Heiselberg, G. Baym, B. Blaettel, L.L. Frankfurt and M. Strikman,
*Color transparency, color opacity and fluctuations in nuclear collisions*,*Phys. Rev. Lett.***67**(1991) 2946 [INSPIRE].ADSCrossRefGoogle Scholar - [11]B. Blaettel, G. Baym, L.L. Frankfurt, H. Heiselberg and M. Strikman,
*Hadronic cross-section fluctuations*,*Phys. Rev.***D 47**(1993) 2761 [INSPIRE].ADSGoogle Scholar - [12]M. Alvioli and M. Strikman,
*Color fluctuation effects in proton-nucleus collisions*,*Phys. Lett.***B 722**(2013) 347 [arXiv:1301.0728] [INSPIRE].ADSCrossRefGoogle Scholar - [13]M. Alvioli, L. Frankfurt, V. Guzey and M. Strikman,
*Revealing “flickering” of the interaction strength in pA collisions at the CERN LHC*,*Phys. Rev.***C 90**(2014) 034914 [arXiv:1402.2868] [INSPIRE].ADSGoogle Scholar - [14]M. Alvioli, B.A. Cole, L. Frankfurt, D.V. Perepelitsa and M. Strikman,
*Evidence for x-dependent proton color fluctuations in pA collisions at the CERN Large Hadron Collider*,*Phys. Rev.***C 93**(2016) 011902 [arXiv:1409.7381] [INSPIRE].ADSGoogle Scholar - [15]M.L. Good and W.D. Walker,
*Diffraction disssociation of beam particles*,*Phys. Rev.***120**(1960) 1857 [INSPIRE].ADSCrossRefGoogle Scholar - [16]ATLAS collaboration,
*Measurement of the centrality dependence of the charged-particle pseudorapidity distribution in proton-lead collisions at*\( \sqrt{s_{NN}}=5.02 \)*TeV with the ATLAS detector*,*Eur. Phys. J.***C 76**(2016) 199 [arXiv:1508.00848] [INSPIRE]. - [17]ALICE collaboration,
*Centrality dependence of particle production in p-Pb collisions at*\( \sqrt{s_{NN}}=5.02 \)*TeV*,*Phys. Rev.***C 91**(2015) 064905 [arXiv:1412.6828] [INSPIRE]. - [18]E. Avsar, G. Gustafson and L. Lönnblad,
*Energy conservation and saturation in small-x evolution*,*JHEP***07**(2005) 062 [hep-ph/0503181] [INSPIRE]. - [19]E. Avsar, G. Gustafson and L. Lönnblad,
*Small-x dipole evolution beyond the large-N*_{c}*imit*,*JHEP***01**(2007) 012 [hep-ph/0610157] [INSPIRE]. - [20]C. Flensburg, G. Gustafson and L. Lönnblad,
*Inclusive and exclusive observables from dipoles in high energy collisions*,*JHEP***08**(2011) 103 [arXiv:1103.4321] [INSPIRE].ADSCrossRefGoogle Scholar - [21]A.H. Mueller,
*Soft gluons in the infinite momentum wave function and the BFKL Pomeron*,*Nucl. Phys.***B 415**(1994) 373 [INSPIRE].ADSCrossRefGoogle Scholar - [22]A.H. Mueller and B. Patel,
*Single and double BFKL Pomeron exchange and a dipole picture of high-energy hard processes*,*Nucl. Phys.***B 425**(1994) 471 [hep-ph/9403256] [INSPIRE]. - [23]B. Andersson, G. Gustafson and B. Nilsson-Almqvist,
*A model for low p*_{T}*hadronic reactions, with generalizations to hadron-nucleus and nucleus-nucleus collisions*,*Nucl. Phys.***B 281**(1987) 289 [INSPIRE].ADSCrossRefGoogle Scholar - [24]H. Pi,
*An event generator for interactions between hadrons and nuclei: FRITIOF version 7.0*,*Comput. Phys. Commun.***71**(1992) 173 [INSPIRE].ADSCrossRefGoogle Scholar - [25]A. Bialas, M. Bleszynski and W. Czyz,
*Multiplicity distributions in nucleus-nucleus collisions at high-energies*,*Nucl. Phys.***B 111**(1976) 461 [INSPIRE].ADSCrossRefGoogle Scholar - [26]A. Bialas,
*Wounded nucleons, wounded quarks: An update*,*J. Phys.***G 35**(2008) 044053 [INSPIRE].ADSCrossRefGoogle Scholar - [27]PHOBOS collaboration, B.B. Back et al.,
*Scaling of charged particle production in d + Au collisions at*\( \sqrt{s_{NN}}=200 \)*GeV*,*Phys. Rev.***C 72**(2005) 031901 [nucl-ex/0409021] [INSPIRE]. - [28]PHENIX collaboration, A. Adare et al.,
*Centrality categorization for R*_{p(d)+A}*in high-energy collisions*,*Phys. Rev.***C 90**(2014) 034902 [arXiv:1310.4793] [INSPIRE]. - [29]ALICE collaboration,
*Pseudorapidity density of charged particles in p + Pb collisions at*\( \sqrt{s_{NN}}=5.02 \)*TeV*,*Phys. Rev. Lett.***110**(2013) 032301 [arXiv:1210.3615] [INSPIRE]. - [30]T. Sjöstrand and M. van Zijl,
*A multiple interaction model for the event structure in hadron collisions*,*Phys. Rev.***D 36**(1987) 2019 [INSPIRE].ADSGoogle Scholar - [31]T. Sjöstrand et al.,
*An introduction to PYTHIA 8.2*,*Comput. Phys. Commun.***191**(2015) 159 [arXiv:1410.3012] [INSPIRE]. - [32]M. Bahr et al.,
*HERWIG++ physics and manual*,*Eur. Phys. J.***C 58**(2008) 639 [arXiv:0803.0883] [INSPIRE].ADSCrossRefGoogle Scholar - [33]T. Gleisberg et al.,
*Event generation with SHERPA 1.1*,*JHEP***02**(2009) 007 [arXiv:0811.4622] [INSPIRE]. - [34]L.D. McLerran and R. Venugopalan,
*Computing quark and gluon distribution functions for very large nuclei*,*Phys. Rev.***D 49**(1994) 2233 [hep-ph/9309289] [INSPIRE]. - [35]C. Flensburg, G. Gustafson and L. Lönnblad,
*Elastic and quasi-elastic pp and γ*^{∗}*p scattering in the dipole model*,*Eur. Phys. J.***C 60**(2009) 233 [arXiv:0807.0325] [INSPIRE].ADSCrossRefGoogle Scholar - [36]C. Flensburg and G. Gustafson,
*Fluctuations, saturation and diffractive excitation in high energy collisions*,*JHEP***10**(2010) 014 [arXiv:1004.5502] [INSPIRE].ADSCrossRefMATHGoogle Scholar - [37]A.H. Mueller,
*O*(2*,*1)*analysis of single particle spectra at high-energy*,*Phys. Rev.***D 2**(1970) 2963 [INSPIRE].ADSGoogle Scholar - [38]E. Gotsman, E. Levin and U. Maor,
*A comprehensive model of soft interactions in the LHC era*,*Int. J. Mod. Phys.***A 30**(2015) 1542005 [arXiv:1403.4531] [INSPIRE].ADSCrossRefMATHGoogle Scholar - [39]V.A. Khoze, A.D. Martin and M.G. Ryskin,
*Elastic scattering and Diffractive dissociation in the light of LHC data*,*Int. J. Mod. Phys.***A 30**(2015) 1542004 [arXiv:1402.2778] [INSPIRE].ADSCrossRefMATHGoogle Scholar - [40]S. Ostapchenko,
*Monte Carlo treatment of hadronic interactions in enhanced Pomeron scheme: I. QGSJET-II model*,*Phys. Rev.***D 83**(2011) 014018 [arXiv:1010.1869] [INSPIRE]. - [41]H.I. Miettinen and J. Pumplin,
*Diffraction scattering and the parton structure of hadrons*,*Phys. Rev.***D 18**(1978) 1696 [INSPIRE].ADSGoogle Scholar - [42]Y. Hatta, E. Iancu, C. Marquet, G. Soyez and D.N. Triantafyllopoulos,
*Diffusive scaling and the high-energy limit of deep inelastic scattering in QCD at large-N*_{c},*Nucl. Phys.***A 773**(2006) 95 [hep-ph/0601150] [INSPIRE]. - [43]E. Avsar, G. Gustafson and L. Lönnblad,
*Diifractive excitation in DIS and pp collisions*,*JHEP***12**(2007) 012 [arXiv:0709.1368] [INSPIRE].ADSGoogle Scholar - [44]G. Gustafson,
*The relation between the Good-Walker and triple-Regge formalisms for diffractive excitation*,*Phys. Lett.***B 718**(2013) 1054 [arXiv:1206.1733] [INSPIRE].ADSCrossRefMATHGoogle Scholar - [45]C. Flensburg, G. Gustafson and L. Lönnblad,
*Exclusive final states in diffractive excitation*,*JHEP***12**(2012) 115 [arXiv:1210.2407] [INSPIRE].ADSCrossRefGoogle Scholar - [46]M. Alvioli, H.J. Drescher and M. Strikman,
*A Monte Carlo generator of nucleon configurations in complex nuclei including Nucleon-Nucleon correlations*,*Phys. Lett.***B 680**(2009) 225 [arXiv:0905.2670] [INSPIRE].ADSCrossRefGoogle Scholar - [47]M. Alvioli, H. Holopainen, K.J. Eskola and M. Strikman,
*Initial state anisotropies and their uncertainties in ultrarelativistic heavy-ion collisions from the Monte Carlo Glauber model*,*Phys. Rev.***C 85**(2012) 034902 [arXiv:1112.5306] [INSPIRE].ADSGoogle Scholar - [48]B. Alver, M. Baker, C. Loizides and P. Steinberg,
*The PHOBOS Glauber Monte Carlo*, arXiv:0805.4411 [INSPIRE]. - [49]C. Loizides, J. Nagle and P. Steinberg,
*Improved version of the PHOBOS Glauber Monte Carlo*,*SoftwareX***1-2**(2015) 13 [arXiv:1408.2549] [INSPIRE].ADSCrossRefGoogle Scholar - [50]L.-K. Ding and E. Stenlund,
*A Monte Carlo for nuclear collision geometry*,*Comput. Phys. Commun.***59**(1990) 313 [INSPIRE].ADSCrossRefGoogle Scholar - [51]G. Antchev et al.,
*First measurement of the total proton-proton cross section at the LHC energy of*\( \sqrt{s}=7 \)*TeV*,*Europhys. Lett.***96**(2011) 21002 [arXiv:1110.1395] [INSPIRE].ADSCrossRefGoogle Scholar - [52]TOTEM collaboration, G. Antchev et al.,
*Measurement of proton-proton elastic scattering and total cross-section at*\( \sqrt{s}=7 \)*TeV*,*Europhys. Lett.***101**(2013) 21002 [INSPIRE]. - [53]TOTEM collaboration, G. Antchev et al.,
*Proton-proton elastic scattering at the LHC energy of*\( \sqrt{s}=7 \)*TeV*,*Europhys. Lett.***95**(2011) 41001 [arXiv:1110.1385] [INSPIRE]. - [54]ALICE collaboration,
*Measurement of inelastic, single- and double-diffraction cross sections in proton-proton collisions at the LHC with ALICE*,*Eur. Phys. J.***C 73**(2013) 2456 [arXiv:1208.4968] [INSPIRE]. - [55]UA4 collaboration, D. Bernard et al.,
*The cross-section of diffraction dissociation at the CERN SPS Collider*,*Phys. Lett.***B 186**(1987) 227 [INSPIRE]. - [56]P. Lipari and M. Lusignoli,
*Interpretation of the measurements of total, elastic and diffractive cross sections at LHC*,*Eur. Phys. J.***C 73**(2013) 2630 [arXiv:1305.7216] [INSPIRE].ADSCrossRefGoogle Scholar - [57]W. Broniowski, M. Rybczynski and P. Bozek,
*GLISSANDO: Glauber initial-state simulation and more. . .*,*Comput. Phys. Commun.***180**(2009) 69 [arXiv:0710.5731] [INSPIRE].ADSCrossRefGoogle Scholar - [58]M. Rybczynski, G. Stefanek, W. Broniowski and P. Bozek,
*GLISSANDO 2 : GLauber Initial-State Simulation AND mOre. . . , ver. 2*,*Comput. Phys. Commun.***185**(2014) 1759 [arXiv:1310.5475] [INSPIRE].ADSCrossRefGoogle Scholar - [59]M. Rybczynski and W. Broniowski,
*Two-body nucleon-nucleon correlations in Glauber-like models*,*Phys. Part. Nucl. Lett.***8**(2011) 992 [arXiv:1012.5607] [INSPIRE].CrossRefGoogle Scholar - [60]A. Bialas,
*Wounded nucleons, wounded quarks: an update*,*J. Phys.***G 35**(2008) 044053.ADSCrossRefGoogle Scholar - [61]B. Andersson, G. Gustafson and H. Pi,
*The FRITIOF model for very high-energy hadronic collisions*,*Z. Phys.***C 57**(1993) 485 [INSPIRE].ADSGoogle Scholar - [62]V.A. Abramovsky, V.N. Gribov and O.V. Kancheli,
*Character of inclusive spectra and fluctuations produced in inelastic processes by multi-Pomeron exchange*,*Yad. Fiz.***18**(1973) 595 [INSPIRE].Google Scholar - [63]A. Buckley et al.,
*Rivet user manual*,*Comput. Phys. Commun.***184**(2013) 2803 [arXiv:1003.0694] [INSPIRE].ADSCrossRefGoogle Scholar - [64]A. Buckley et al.,
*HepData and JetWeb: HEP data archiving and model validation*, talk given at the 15^{th}*International Conference on Computing in High Energy and Nuclear Physics (CHEP 2006)*, February 13-17, Mumbai, India (2006), hep-ph/0605048 [INSPIRE]. - [65]CMS collaboration,
*Nuclear effects on the transverse momentum spectra of charged particles in pPb collisions at*\( \sqrt{s_{NN}}=5.02 \)*TeV*,*Eur. Phys. J.***C 75**(2015) 237 [arXiv:1502.05387] [INSPIRE]. - [66]H1 collaboration, A. Aktas et al.,
*Measurement and QCD analysis of the diffractive deep-inelastic scattering cross-section at HERA*,*Eur. Phys. J.***C 48**(2006) 715 [hep-ex/0606004] [INSPIRE]. - [67]C. Bierlich, G. Gustafson, L. Lönnblad and A. Tarasov,
*Effects of overlapping strings in pp collisions*,*JHEP***03**(2015) 148 [arXiv:1412.6259] [INSPIRE].CrossRefGoogle Scholar - [68]C. Bierlich and J.R. Christiansen,
*Effects of color reconnection on hadron flavor observables*,*Phys. Rev.***D 92**(2015) 094010 [arXiv:1507.02091] [INSPIRE].ADSGoogle Scholar - [69]J.R. Christiansen and P.Z. Skands,
*String formation beyond leading colour*,*JHEP***08**(2015) 003 [arXiv:1505.01681] [INSPIRE].ADSCrossRefGoogle Scholar - [70]ALICE collaboration,
*Multiplicity-dependent enhancement of strange and multi-strange hadron production in proton-proton collisions at*\( \sqrt{s}=7 \)*TeV*, arXiv:1606.07424 [INSPIRE]. - [71]I. Altsybeev,
*Mean transverse momenta correlations in hadron-hadron collisions in MC toy model with repulsing strings*,*AIP Conf. Proc.***1701**(2016) 100002 [arXiv:1502.03608] [INSPIRE].CrossRefGoogle Scholar