New results are presented on a high-statistics measurement of Collins and Sivers asymmetries of charged hadrons produced in deep inelastic scattering of muons on a transversely polarised $^6$LiD target. The data were taken in 2022 with the COMPASS spectrometer using the 160 \gevv\ muon beam at CERN, balancing the existing data on transversely polarised proton targets. The first results from about two-thirds of the new data have total uncertainties smaller by up to a factor of three compared to the previous deuteron measurements. Using all the COMPASS proton and deuteron results, both the transversity and the Sivers distribution functions of the $u$ and $d$ quark, as well as the tensor charge in the measured $x$-range are extracted. In particular, the accuracy of the $d$ quark results is significantly improved.

Compass

10.48550/arxiv.2401.00309

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Design of beam optics for RF-separated kaon and antiproton beams in the M2 beam line of the CERN North Area

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment (2022)

Alexander Gerbershagen V. Andrieux J. Bernhard M. Brugger О. Денисов

The present contribution reviews the principle of RF separation and explains its dependence on different parameters of beam optics and hardware. The first examination of potential showstoppers for the RF-separated beam implementation for Phase-2 of the AMBER experiment in the M2 beam line of the North Area is presented. Different beam optics settings have been examined, providing either focused or parallel beams inside the RF cavities. The separation and transmission capability of the different optics settings for realistic characteristics of RF cavities are discussed and the preliminary results of the potential purity and intensity of the RF-separated beam are presented. These show that a trade-off between the overall beam intensity and the share of the required particle type in the overall beam needs to be established. No showstoppers have been identified for achieving the beam parameters required for AMBER's kaonic Primakoff reactions, kaon spectroscopy, prompt-photon production and kaon charge-radius programs. However, the high beam intensity requirements of the AMBER Drell–Yan programme cannot be satisfied with an RF-separated beam.

Antiproton

10.1016/j.nima.2022.168004

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Study of and annihilation reactions in flight

Nuclear Physics A (1999)

A. Filippi M. Agnello F. Balestra D. Bergo E. Botta

Annihilation

Momentum (technical analysis)

10.1016/s0375-9474(99)00157-8

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Limits on the mass of the light Higgs boson from decays of π, K, and η' mesons in a proton beam-dump experiment

Physics of Atomic Nuclei (1992)

L.S. Barabash S.A. Baranov Yu.A. Batusov S.A. Bunyatov V. Valuev

Source

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Method for determining the planned position of the tacking pointsat performing the measuring work on the inner water area

О. Денисов А. Задемленюк О. Лісник В. Жидков O. Denysov

Запропоновано спосіб проведення промірних робіт на внутрішніх водоймах з використанням навігаційного GPS-приймача типу Magellan.

Tacking

Position (finance)

Source

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Development of a THGEM-based photon detector for RICH applications

Nuovo Cimento Della Societa Italiana Di Fisica A-nuclei Particles and Fields (2009)

M. Alekseev M. Alfonsi R. Birsa F. Bradamante A. Bressan

10.1393/ncc/i2009-10500-y

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The gain in Thick GEM multipliers and its time-evolution

Journal of Instrumentation (2015)

M. Alexeev R. Birsa F. Bradamante A. Bressan M. Büchele

In the context of a project to upgrade the gas photon detectors of COMPASS RICH-1, we have performed an R&D programme aimed to develop photon detectors based on multi-layer arrangements of thick GEM electron multipliers coupled to a CsI photoconverter. For this purpose, thick GEMs have been characterised in detail including the gain performance, its dependance on the geometrical parameters and its time-evolution, a feature exhibited by the gas detectors with open insulator surfaces. The variation due to this evolution drammatically depends on the parameters themselves. In the present article we summarise the outcomes of the studies dedicated to the thick GEM gain and its evolution versus time. We also include a qualitative model which accounts for the peculiar details of the observed thick GEM gain time-evolution.

10.1088/1748-0221/10/03/p03026

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Transverse-momentum-dependent multiplicities of charged hadrons in muon-deuteron deep inelastic scattering

Physical review. D/Physical review. D. (2018)

M. Aghasyan M. Alexeev G.D. Alexeev A. Amoroso V. Andrieux

A semi-inclusive measurement of charged hadron multiplicities in deep inelastic muon scattering off an isoscalar target was performed using data collected by the COMPASS Collaboration at CERN. The following kinematic domain is covered by the data: photon virtuality ${Q}^{2}>1\text{ }\text{ }(\mathrm{GeV}/c{)}^{2}$, invariant mass of the hadronic system $W>5\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, Bjorken scaling variable in the range $0.003

Virtual particle

Perturbative QCD

10.1103/physrevd.97.032006

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Citations (59)