We present the first measurement at the LHC of exclusive J=ψ photoproduction off protons, in pffiffiffiffiffiffiffi ultraperipheral proton-lead collisions at sNN 1⁄4 5.02 TeV. Events are selected with a dimuon pair produced either in the rapidity interval, in the laboratory frame, 2.5 < y < 4 (p-Pb) or −3.6 < y < −2.6 (Pb-p), and no other particles observed in the ALICE acceptance. The measured cross sections σðγ þ p → J=ψ þ pÞ are 33.2 2.2ðstatÞ 3.2ðsystÞ 0.7ðtheorÞ nb in p-Pb and 284 36ðstatÞþ27ðsystÞ −32 26ðtheorÞ nb in Pb-p collisions. We measure this process up to about 700 GeV in the γp center of mass, which is a factor of two larger than the highest energy studied at HERA. The data are consistent with a power law dependence of the J=ψ photoproduction cross section in γp energies from about 20 to 700 GeV, or equivalently, from Bjorken x scaling variable between ∼2 × 10−2 and ∼2 × 10−5, thus indicating no significant change in the gluon density behavior of the proton between HERA and LHC energies.
Eser Adı (dc.title) | Exclusive J/ψ photoproduction off protons in ultra-peripheral p-Pb collisions at sNN−−−√=5.02 TeV |
Yayın Türü (dc.type) | Makale |
Yazar/lar (dc.contributor.author) | KARASU UYSAL, Ayben |
Yazar/lar (dc.contributor.author) | ALICE Collaboration |
DOI Numarası (dc.identifier.doi) | http://dx.doi.org/10.1103/PhysRevLett.113.232504 |
Atıf Dizini (dc.source.database) | Wos |
Atıf Dizini (dc.source.database) | Scopus |
Konu Başlıkları (dc.subject) | ALICE |
Konu Başlıkları (dc.subject) | LHC |
Konu Başlıkları (dc.subject) | J/psi Photoproduction |
Yayın Tarihi (dc.date.issued) | 2014 |
Kayıt Giriş Tarihi (dc.date.accessioned) | 2019-07-05T11:18:26Z |
Açık Erişim tarihi (dc.date.available) | 2019-07-05T11:18:26Z |
Orcid (dc.identifier.orcid) | 0000-0001-6297-2532 |
Özet (dc.description.abstract) | We present the first measurement at the LHC of exclusive J=ψ photoproduction off protons, in pffiffiffiffiffiffiffi ultraperipheral proton-lead collisions at sNN 1⁄4 5.02 TeV. Events are selected with a dimuon pair produced either in the rapidity interval, in the laboratory frame, 2.5 < y < 4 (p-Pb) or −3.6 < y < −2.6 (Pb-p), and no other particles observed in the ALICE acceptance. The measured cross sections σðγ þ p → J=ψ þ pÞ are 33.2 2.2ðstatÞ 3.2ðsystÞ 0.7ðtheorÞ nb in p-Pb and 284 36ðstatÞþ27ðsystÞ −32 26ðtheorÞ nb in Pb-p collisions. We measure this process up to about 700 GeV in the γp center of mass, which is a factor of two larger than the highest energy studied at HERA. The data are consistent with a power law dependence of the J=ψ photoproduction cross section in γp energies from about 20 to 700 GeV, or equivalently, from Bjorken x scaling variable between ∼2 × 10−2 and ∼2 × 10−5, thus indicating no significant change in the gluon density behavior of the proton between HERA and LHC energies. |
Tek Biçim Adres (dc.identifier.uri) | https://hdl.handle.net/20.500.12498/499 |