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20th LOMONOSOV CONFERENCE ON ELEMENTARY PARTICLE PHYSICS
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Heavy-Ion Physics at CMS
Sergey Petrushanko (CMS Collaboration)
E-mail: Serguei.Petrouchanko@cern.ch
Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University. Moscow, Russia
Received January 9, 2022
We present a selection of recent results by the CMS collaboration on heavy-ion physics.
Keywords: relativistic heavy-ion collisions, quark-gluon plasma, elliptic flow, quarkonia, jets.
English version: Moscow University Physics Bulletin. 2022. 77, No. 2. Pp. 247-249.
Polarised Study of Diboson Production at NNLO
Andrei Popescu E-mail: popescu@hep.phy. cam. ac.uk
Cavendish Laboratory, University of Cambridge. Cambridge, United Kingdom Received February 10, 2022
We perform the first polarisation study [1] at next-to-next-to-leading order (NNLO) QCD for the leptonic signature of the diboson production process (pp^ e+ve^-i?M), in the fiducial setup inspired by experimental measurements at ATLAS. We present the results and investigate NNLO effects arising in differential distributions. Calculation is performed within the framework of double-pole approximation.
Keywords: NNLO, QCD, polarisation, bosons.
English version: Moscow University Physics Bulletin. 2022. 77, No. 2. Pp. 252-253.
Search for Rare Kaon Decays at the J-PARC KOTO Experiment
Koji Shiomi (KOTO Collaboration) E-mail: shiomi@post.kek.jp
Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK),
Tsukuba, Ibaraki 305-0801, Japan Received January 17, 2022
The KOTO experiment at the J-PARC 30GeV Main Ring is dedicated to search for the rare decay I\l —> iftvv. This mode directly breaks the CP symmetry and is highly suppressed in the Standard Model (SM). In addition, the theoretical uncertainties on the decay is only a few percent. Those features make this decay one of the best probes to search for new physics beyond the SM. We have been accumulating physics data since 2013 and we had finalized the analysis with the dataset taken in 2016-2018. In the analysis, we found charged kaons contained in the neutral beam could become a serious background source. Thus, we have installed a new counter to detect the charged kaons and resumed physics data taking. In this parper, we report the results of the 2016-2018 analysis and the status of recent data taking.
Keywords: rare kaon decays, collider physics, CP violation.
English version: Moscow University Physics Bulletin. 2022. 77, No. 2. Pp. 254-259.
Self-Similarity of K°s-Meson Production in Au+Au Collisions at RHIC
Mikhail Tokarev1'", Imrich Zborovsky2'6 E-mail: atokarev@jinr.ru, bzborovsky@ujf.cas.cz
1 Joint Institute for Nuclear Research. Dubna, , 141980, Russia 1 Nuclear Physics Institute, Academy of Sciences of the Czech Republic, ReZ, Czech Republic
Received December 28, 2021
New results of analysis of K0-meson spectra in Au + Au collisions obtained by the STAR Collaboration at RHIC using the z-scaling approach are presented. The spectra were measured over a wide range of collision energy yfsNN = 7.7 — 200 GeV, transverse momentum of produced particles and different centralities in the rapidity range |y| < 0.5. The self-similarity of the K0 spectra in z-presentation is demonstrated. The energy loss as a function of the collision energy and the transverse momentum of K0 meson for 0-5% centrality is estimated.
Keywords: high energy, nucleus collisions, hadron spectrum, self-similarity, energy loss, strange probe.
English version: Moscow University Physics Bulletin. 2022. 77, No. 2. Pp. 260-262.
