تقرير
Measurement of an excess in the yield of J/$\psi$ at very low-$p_{\rm T}$ in Pb--Pb collisions with the ALICE detector
| العنوان: | Measurement of an excess in the yield of J/$\psi$ at very low-$p_{\rm T}$ in Pb--Pb collisions with the ALICE detector |
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| المؤلفون: | Massacrier, Laure |
| سنة النشر: | 2015 |
| المجموعة: | High Energy Physics - Experiment Nuclear Experiment |
| مصطلحات موضوعية: | Nuclear Experiment, High Energy Physics - Experiment |
| الوصف: | We report on the measurement of J/$\psi$ production at very low transverse momentum ($p_{\rm T} < $ 300 MeV/$c$) in Pb--Pb collisions performed with the ALICE detector at the LHC. We find an excess in the yield of J/$\psi$ with respect to expectations from hadronic production. Coherent photo-production of J/$\psi$ is proposed as a plausible origin of this excess. We show the nuclear modification factor of very low-$p_{\rm T}$ J/$\psi$ as a function of centrality. Then we measure the J/$\psi$ coherent photoproduction cross section in peripheral events assuming that it is the mechanism at the origin of the measured excess. It's worth noting that the observation of J/$\psi$ coherent photoproduction in Pb--Pb collisions at impact parameters smaller than twice the nuclear radius has never been observed so far and would open new theoretical challenges. Comment: Proceeding of EDS Blois Conference, 29th June - 4th July 2015, Borgo, Corsica |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/1510.08315 |
| رقم الأكسشن: | edsarx.1510.08315 |
| قاعدة البيانات: | arXiv |
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