The production of thecharmonium state was measured with ALICE in Pb-Pb collisions at, in the dimuon decay channel. A significant signal was observed for the first time at LHC energies down to zero transverse momentum, at forward rapidity (). The measurement of the ratio of the inclusive production cross sections of theandresonances is reported as a function of the centrality of the collisions and of transverse momentum, in the region. The results are compared with the corresponding measurements incollisions, by forming the double ratio. It is found that in Pb-Pb collisions theis suppressed by a factor ofwith respect to the. Thenuclear modification factorwas also obtained as a function of both centrality and. The results show that theresonance yield is strongly suppressed in Pb-Pb collisions, by a factor of up towith respect to. Comparisons of cross section ratios with previous Super Proton Synchrotron findings by the NA50 experiment and ofwith higher-results at LHC energy are also reported. These results and the corresponding comparisons with calculations of transport and statistical models address questions on the presence and properties of charmonium states in the quark-gluon plasma formed in nuclear collisions at the LHC.
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We measure the tau-to-light-lepton ratio of inclusive-meson branching fractions, whereindicates an electron or muon, and thereby test the universality of charged-current weak interactions. We select events that have one fully reconstructedmeson and a charged lepton candidate fromof electron-positron collision data collected with the Belle II detector. We find, in agreement with standard-model expectations. This is the first direct measurement of.
- Award ID(s):
- 2209481
- NSF-PAR ID:
- 10527129
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- https://doi.org/10.1103/PhysRevLett.132.211804
- Date Published:
- Journal Name:
- Physical Review Letters
- Volume:
- 132
- Issue:
- 21
- ISSN:
- 0031-9007
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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