Antiproton over proton and K− over K+ multiplicity ratios at high z in DIS

The COMPASS Collaboration

doi:10.1016/j.physletb.2020.135600

Antiproton over proton and K⁻ over K⁺ multiplicity ratios at high z in DIS

The COMPASS Collaboration

Research output: Contribution to journal › Article › peer-review

Abstract

The antiparticle-over-particle multiplicity ratio is measured in deep-inelastic scattering for negatively and positively charged kaons and, for the first time, for antiprotons and protons. The data were obtained by the COMPASS Collaboration using a 160 GeV muon beam impinging on an isoscalar ⁶LiD target. The regime of deep-inelastic scattering is ensured by requiring Q² > 1 (GeV/c)² for the photon virtuality and W>5 GeV/c² for the invariant mass of the produced hadronic system. Bjorken-x is restricted to the range 0.01 to 0.40. Protons and antiprotons are identified in the momentum range from 20 GeV/c to 60 GeV/c and required to carry a large fraction of the virtual-photon energy, z>0.5. In the whole studied z-region, the p¯ over p multiplicity ratio is found to be below the lower limit expected from calculations based on leading-order perturbative Quantum Chromodynamics (pQCD). Kaons were previously analysed in the momentum range 12 GeV/c to 40 GeV/c. In the present analysis this range is extended up to 55 GeV/c, whereby events with larger virtual-photon energies are included in the analysis and the observed K⁻ over K⁺ ratio becomes closer to the expectation of next-to-leading order pQCD. The results of both analyses strengthen our earlier conclusion that at COMPASS energies the phase space available for single-hadron production in deep-inelastic scattering should be taken into account in the standard pQCD formalism.

Original language	English (US)
Article number	135600
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	807
DOIs	https://doi.org/10.1016/j.physletb.2020.135600
State	Published - Aug 10 2020

Keywords

COMPASS
Deep-inelastic scattering
Hadron multiplicities
Quantum chromodynamics
pQCD

ASJC Scopus subject areas

Nuclear and High Energy Physics

Online availability

10.1016/j.physletb.2020.135600

Library availability

Discover UIUC Full Text

Cite this

@article{791bc6660aac43d2a13132699f809fd3,

title = "Antiproton over proton and K− over K+ multiplicity ratios at high z in DIS",

abstract = "The antiparticle-over-particle multiplicity ratio is measured in deep-inelastic scattering for negatively and positively charged kaons and, for the first time, for antiprotons and protons. The data were obtained by the COMPASS Collaboration using a 160 GeV muon beam impinging on an isoscalar 6LiD target. The regime of deep-inelastic scattering is ensured by requiring Q2 > 1 (GeV/c)2 for the photon virtuality and W>5 GeV/c2 for the invariant mass of the produced hadronic system. Bjorken-x is restricted to the range 0.01 to 0.40. Protons and antiprotons are identified in the momentum range from 20 GeV/c to 60 GeV/c and required to carry a large fraction of the virtual-photon energy, z>0.5. In the whole studied z-region, the p¯ over p multiplicity ratio is found to be below the lower limit expected from calculations based on leading-order perturbative Quantum Chromodynamics (pQCD). Kaons were previously analysed in the momentum range 12 GeV/c to 40 GeV/c. In the present analysis this range is extended up to 55 GeV/c, whereby events with larger virtual-photon energies are included in the analysis and the observed K− over K+ ratio becomes closer to the expectation of next-to-leading order pQCD. The results of both analyses strengthen our earlier conclusion that at COMPASS energies the phase space available for single-hadron production in deep-inelastic scattering should be taken into account in the standard pQCD formalism.",

keywords = "COMPASS, Deep-inelastic scattering, Hadron multiplicities, Quantum chromodynamics, pQCD",

author = "{The COMPASS Collaboration} and Alexeev, {G. D.} and Alexeev, {M. G.} and A. Amoroso and V. Andrieux and V. Anosov and A. Antoshkin and K. Augsten and W. Augustyniak and Azevedo, {C. D.R.} and B. Bade{\l}ek and F. Balestra and M. Ball and J. Barth and R. Beck and Y. Bedfer and {Berenguer Antequera}, J. and J. Bernhard and M. Bodlak and F. Bradamante and A. Bressan and M. B{\"u}chele and Burtsev, {V. E.} and Chang, {W. C.} and C. Chatterjee and M. Chiosso and Chumakov, {A. G.} and Chung, {S. U.} and A. Cicuttin and Correia, {P. M.M.} and Crespo, {M. L.} and D. D'Ago and {Dalla Torre}, S. and Dasgupta, {S. S.} and S. Dasgupta and I. Denisenko and Denisov, {O. Yu} and Donskov, {S. V.} and N. Doshita and Ch Dreisbach and W. D{\"u}nnweber and Dusaev, {R. R.} and A. Efremov and Eversheim, {P. D.} and P. Faccioli and M. Faessler and M. Finger and {Grosse Perdekamp}, M. and N. Makins and Peng, {J. C.} and C. Riedl",

note = "Publisher Copyright: {\textcopyright} 2020",

year = "2020",

month = aug,

day = "10",

doi = "10.1016/j.physletb.2020.135600",

language = "English (US)",

volume = "807",

journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",

issn = "0370-2693",

publisher = "Elsevier B.V.",

}

TY - JOUR

T1 - Antiproton over proton and K− over K+ multiplicity ratios at high z in DIS

AU - The COMPASS Collaboration

AU - Alexeev, G. D.

AU - Alexeev, M. G.

AU - Amoroso, A.

AU - Andrieux, V.

AU - Anosov, V.

AU - Antoshkin, A.

AU - Augsten, K.

AU - Augustyniak, W.

AU - Azevedo, C. D.R.

AU - Badełek, B.

AU - Balestra, F.

AU - Ball, M.

AU - Barth, J.

AU - Beck, R.

AU - Bedfer, Y.

AU - Berenguer Antequera, J.

AU - Bernhard, J.

AU - Bodlak, M.

AU - Bradamante, F.

AU - Bressan, A.

AU - Büchele, M.

AU - Burtsev, V. E.

AU - Chang, W. C.

AU - Chatterjee, C.

AU - Chiosso, M.

AU - Chumakov, A. G.

AU - Chung, S. U.

AU - Cicuttin, A.

AU - Correia, P. M.M.

AU - Crespo, M. L.

AU - D'Ago, D.

AU - Dalla Torre, S.

AU - Dasgupta, S. S.

AU - Dasgupta, S.

AU - Denisenko, I.

AU - Denisov, O. Yu

AU - Donskov, S. V.

AU - Doshita, N.

AU - Dreisbach, Ch

AU - Dünnweber, W.

AU - Dusaev, R. R.

AU - Efremov, A.

AU - Eversheim, P. D.

AU - Faccioli, P.

AU - Faessler, M.

AU - Finger, M.

AU - Grosse Perdekamp, M.

AU - Makins, N.

AU - Peng, J. C.

AU - Riedl, C.

PY - 2020/8/10

Y1 - 2020/8/10

N2 - The antiparticle-over-particle multiplicity ratio is measured in deep-inelastic scattering for negatively and positively charged kaons and, for the first time, for antiprotons and protons. The data were obtained by the COMPASS Collaboration using a 160 GeV muon beam impinging on an isoscalar 6LiD target. The regime of deep-inelastic scattering is ensured by requiring Q2 > 1 (GeV/c)2 for the photon virtuality and W>5 GeV/c2 for the invariant mass of the produced hadronic system. Bjorken-x is restricted to the range 0.01 to 0.40. Protons and antiprotons are identified in the momentum range from 20 GeV/c to 60 GeV/c and required to carry a large fraction of the virtual-photon energy, z>0.5. In the whole studied z-region, the p¯ over p multiplicity ratio is found to be below the lower limit expected from calculations based on leading-order perturbative Quantum Chromodynamics (pQCD). Kaons were previously analysed in the momentum range 12 GeV/c to 40 GeV/c. In the present analysis this range is extended up to 55 GeV/c, whereby events with larger virtual-photon energies are included in the analysis and the observed K− over K+ ratio becomes closer to the expectation of next-to-leading order pQCD. The results of both analyses strengthen our earlier conclusion that at COMPASS energies the phase space available for single-hadron production in deep-inelastic scattering should be taken into account in the standard pQCD formalism.

AB - The antiparticle-over-particle multiplicity ratio is measured in deep-inelastic scattering for negatively and positively charged kaons and, for the first time, for antiprotons and protons. The data were obtained by the COMPASS Collaboration using a 160 GeV muon beam impinging on an isoscalar 6LiD target. The regime of deep-inelastic scattering is ensured by requiring Q2 > 1 (GeV/c)2 for the photon virtuality and W>5 GeV/c2 for the invariant mass of the produced hadronic system. Bjorken-x is restricted to the range 0.01 to 0.40. Protons and antiprotons are identified in the momentum range from 20 GeV/c to 60 GeV/c and required to carry a large fraction of the virtual-photon energy, z>0.5. In the whole studied z-region, the p¯ over p multiplicity ratio is found to be below the lower limit expected from calculations based on leading-order perturbative Quantum Chromodynamics (pQCD). Kaons were previously analysed in the momentum range 12 GeV/c to 40 GeV/c. In the present analysis this range is extended up to 55 GeV/c, whereby events with larger virtual-photon energies are included in the analysis and the observed K− over K+ ratio becomes closer to the expectation of next-to-leading order pQCD. The results of both analyses strengthen our earlier conclusion that at COMPASS energies the phase space available for single-hadron production in deep-inelastic scattering should be taken into account in the standard pQCD formalism.

KW - COMPASS

KW - Deep-inelastic scattering

KW - Hadron multiplicities

KW - Quantum chromodynamics

KW - pQCD

UR - http://www.scopus.com/inward/record.url?scp=85087686810&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85087686810&partnerID=8YFLogxK

U2 - 10.1016/j.physletb.2020.135600

DO - 10.1016/j.physletb.2020.135600

M3 - Article

AN - SCOPUS:85087686810

SN - 0370-2693

VL - 807

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

M1 - 135600

ER -