K. Koenigsmann

Transverse target spin asymmetries in exclusive $I ¨ ^{0}$ muoproduction

C. Adolph, M. G. Alekseev, V. Yu. Alexakhin +209

Exclusive production of $I ¨ ^{0}$ mesons was studied at the COMPASS experiment by scattering 160 GeV/ $c$ muons off transversely polarised protons. Five single-spin and three double-sp…

Measurement of the Cross Section for High-p_T Hadron Production in Scattering of 160 GeV/c Muons off Nucleons

C. Adolph, M. G. Alekseev, V. Yu. Alexakhin +209

The differential cross section for production of charged hadrons with high transverse momenta in scattering of 160\,GeV/ $c$ muons off nucleons at low photon virtualities has been m…

Exclusive $I ¨ $ meson muoproduction on transversely polarised protons

C. Adolph, J. Agarwala, M. Aghasyan +225

Exclusive production of $I ¨ $ mesons was studied at the COMPASS experiment by scattering $160 GeV / c$ muons off transversely polarised protons. Five single-spin and…

Study of Î£(1385) and Î(1321) hyperon and antihyperon production in deep inelastic muon scattering

C. Adolph, M. Alekseev, V. Yu. Alexakhin +203

Large samples of Î, Î£(1385) and Î(1321) hyperons produced in deep-inelastic muon scattering off a ^6LiD target were collected with the COMPASS experimental setup at CERN. The re…

physics.ins-det2017

Status of COMPASS RICH-1 Upgrade with MPGD-based Photon Detectors

M. Alexeev, R Birsa, F. Bradamante +31

A Set of new MPGD-based Photon Detectors is being built for the upgrade of COMPASS RICH-1. The detectors cover a total active area of 1.4 m $^{2}$ and are based on a hybrid architectu…

Search for exclusive photoproduction of Z $_{c}^{\pm}$ (3900) at COMPASS

C. Adolph, R. Akhunzyanov, M. G. Alexeev +205

A search for the exclusive production of the $Z_{c}^{\pm} (3900)$ hadron by virtual photons has been performed in the channel $Z_{c}^{\pm} (3900) \to J / I ¨ I ¨ ^{\pm}$ . The data cover…

First measurement of transverse-spin-dependent azimuthal asymmetries in the Drell-Yan process

Aghasyan, R. Akhunzyanov, M. G. Alexeev +216

The first measurement of transverse-spin-dependent azimuthal asymmetries in the pion-induced Drell-Yan (DY) process is reported. We use the CERN SPS 190 GeV/ $c$ , $I ¨ ^{-}$ beam and…

Measurement of azimuthal hadron asymmetries in semi-inclusive deep inelastic scattering off unpolarised nucleons

C. Adolph, R. Akhunzyanov, M. G. Alekseev +217

Spin-averaged asymmetries in the azimuthal distributions of positive and negative hadrons produced in deep inelastic scattering were measured using the CERN SPS muon beam at $160$ …

Experimental investigation of transverse spin asymmetries in muon-p SIDIS processes: Sivers asymmetries

C. Adolph, M. G. Alekseev, V. Yu. Alexakhin +215

The COMPASS Collaboration at CERN has measured the transverse spin azimuthal asymmetry of charged hadrons produced in semi-inclusive deep inelastic scattering using a 160 GeV posit…

Sivers asymmetry extracted in SIDIS at the hard scale of the Drell-Yan process at COMPASS

C. Adolph, M. Aghasyan, R. Akhunzyanov +223

Proton transverse-spin azimuthal asymmetries are extracted from the COMPASS 2010 semi-inclusive hadron measurements in deep inelastic muon-nucleon scattering in those four regions…

A high-statistics measurement of transverse spin effects in dihadron production from muon-proton semi-inclusive deep-inelastic scattering

C. Adolph, R. Akhunzyanov, M. G. Alekseev +217

A measurement of the azimuthal asymmetry in dihadron production in deep-inelastic scattering of muons on transversely polarised proton (NH $_{3}$ ) targets are presented. They provid…

hep-ex2015

The Spin Structure Function $g_{1}^{p}$ of the Proton and a Test of the Bjorken Sum Rule

C. Adolph, R. Akhunzyanov, M. G. Alexeev +203

New results for the double spin asymmetry $A_{1}^{p}$ and the proton longitudinal spin structure function $g_{1}^{p}$ are presented. They were obtained by the COMPASS collabora…

Final COMPASS results on the deuteron spin-dependent structure function $g_{1}^{d}$ and the Bjorken sum rule

C. Adolph, M. Aghasyan, R. Akhunzyanov +223

Final results are presented from the inclusive measurement of deep-inelastic polarised-muon scattering on longitudinally polarised deuterons using a $^{6}$ LiD target. The data were t…

Multiplicities of charged kaons from deep-inelastic muon scattering off an isoscalar target

C. Adolph, J. Agarwala, M. Aghasyan +223

Precise measurements of charged-kaon multiplicities in deep inelastic scattering were performed. The results are presented in three-dimensional bins of the Bjorken scaling variable…

hep-ex2018

Search for muoproduction of $X (3872)$ at COMPASS and indication of a new state $X (3872)$

M. Aghasyan, R. Akhunzyanov, M. G. Alexeev +224

We have searched for exclusive production of exotic charmonia in the reaction $I^¼^{+} N \to I^¼^{+} (J / I ¨ I ¨ ^{+} I ¨ ^{-}) I ¨ ^{\pm} N^{'}$ using COMPASS data collected with incoming muo…

hep-ph2017

New analysis of $I^\cdot I ¨ $ tensor resonances measured at the COMPASS experiment

A. Jackura, C. Fernandez-Ramirez, M. Mikhasenko +232

We present a new amplitude analysis of the $I^\cdot I ¨ $ $D$ -wave in $I ¨ ^{-} p \to I^\cdot I ¨ ^{-} p$ measured by COMPASS. Employing an analytical model based on the principles of the relativistic $S…

physics.ins-det2014

The COMPASS Setup for Physics with Hadron Beams

Ph. Abbon, C. Adolph, R. Akhunzyanov +228

The main characteristics of the COMPASS experimental setup for physics with hadron beams are described. This setup was designed to perform exclusive measurements of processes with…

D* and D Meson Production in Muon Nucleon Interactions at 160 GeV/c

C. Adolph, M. G. Alekseev, V. Yu. Alexakhin +217

The production of D* and D mesons in inelastic scattering of 160 GeV/c muons off a ^6LiD target has been investigated with the COMPASS spectrometer at CERN for 0.003 (GeV/c)^2 < Q^…

Observation of a new narrow axial-vector meson $a_{1} (1420)$

C. Adolph, R. Akhunzyanov, M. G. Alexeev +201

The COMPASS collaboration at CERN has measured diffractive dissociation of 190 GeV/ $c$ pions into the $I ¨ ^{-} I ¨ ^{-} I ¨ ^{+}$ final state using a stationary hydrogen target. A partial-wave…

Multiplicities of charged pions and unidentified charged hadrons from deep-inelastic scattering of muons off an isoscalar target

C. Adolph, J. Agarwala, M. Aghasyan +224

Multiplicities of charged pions and unidentified hadrons produced in deep-inelastic scattering were measured in bins of the Bjorken scaling variable $x$ , the relative virtual-photo…

hep-ex2015

Measurement of the charged-pion polarisability

C. Adolph, R. Akhunzyanov, M. G. Alexeev +210

The COMPASS collaboration at CERN has investigated pion Compton scattering, $I ¨ ^{-} I^^{3} \to I ¨ ^{-} I^^{3}$ , at centre-of-mass energy below 3.5 pion masses. The process is embedded in t…

Collins and Sivers asymmetries in muonproduction of pions and kaons off transversely polarised proton

C. Adolph, R. Akhunzyanov, M. G. Alexeev +205

Measurements of the Collins and Sivers asymmetries for charged pions and charged and neutral kaons produced in semi-inclusive deep-inelastic scattering of high energy muons off tra…

Odd and Even Partial Waves of $I^\cdot I ¨ ^{-}$ and $I^\cdot^{'} I ¨ ^{-}$ in $I ¨ ^{-} p \to I^\cdot^{(')} I ¨ ^{-} p$ at $191 GeV / c$

C. Adolph, R. Akhunzyanov, M. G. Alexeev +205

Exclusive production of $I^\cdot I ¨ ^{-}$ and $I^\cdot^{'} I ¨ ^{-}$ has been studied with a $191 GeV / c$ $I ¨ ^{-}$ beam impinging on a hydrogen target at COMPASS (CERN). Partial-wave analyses rev…

Leading-order determination of the gluon polarisation from semi-inclusive deep inelastic scattering data

C. Adolph, M. Aghasyan, R. Akhunzyanov +217

Using a novel analysis technique, the gluon polarisation in the nucleon is re-evaluated using the longitudinal double-spin asymmetry measured in the cross section of semi-inclusive…

Transverse spin effects in hadron-pair production from semi-inclusive deep inelastic scattering

C. Adolph, M. G. Alekseev, V. Yu. Alexakhin +212

First measurements of azimuthal asymmetries in hadron-pair production in deep-inelastic scattering of muons on transversely polarised ^6LiD (deuteron) and NH_3 (proton) targets are…

Transverse-momentum-dependent Multiplicities of Charged Hadrons in Muon-Deuteron Deep Inelastic Scattering

M. Aghasyan, R. Akhunzyanov, M. G. Alexeev +227

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 Collaborat…

Leading order determination of the gluon polarisation from DIS events with high-p_T hadron pairs

C. Adolph, M. G. Alekseev, V. Yu. Alexakhin +212

We present a determination of the gluon polarisation Delta g/g in the nucleon, based on the longitudinal double-spin asymmetry of DIS events with a pair of large transverse-momentu…

hep-ex2018

Azimuthal asymmetries of charged hadrons produced in high-energy muon scattering off longitudinally polarised deuterons

C. Adolph, M. Aghasyan, R. Akhunzyanov +221

Single hadron azimuthal asymmetries of positive and negative hadrons produced in muon semi-inclusive deep inelastic scattering off longitudinally polarised deuterons are determined…

Leading and Next-to-Leading Order Gluon Polarisation in the Nucleon and Longitudinal Double Spin Asymmetries from Open Charm Muoproduction

C. Adolph, M. G. Alekseev, V. Yu. Alexakhin +217

The gluon polarisation in the nucleon was measured using open charm production by scattering 160 GeV/c polarised muons off longitudinally polarised protons or deuterons. The data w…

Longitudinal double-spin asymmetry $A_{1}^{p}$ and spin-dependent structure function $g_{1}^{p}$ of the proton at small values of $x$ and $Q^{2}$

M. Aghasyan, R. Akhunzyanov, M. G. Alexeev +225

We present a precise measurement of the proton longitudinal double-spin asymmetry $A_{1}^{p}$ and the proton spin-dependent structure function $g_{1}^{p}$ at photon virtualitie…

Experimental investigation of transverse spin asymmetries in muon-p SIDIS processes: Collins asymmetries

C. Adolph, M. G. Alekseev, V. Yu. Alexakhin +215

The COMPASS Collaboration at CERN has measured the transverse spin azimuthal asymmetry of charged hadrons produced in semi-inclusive deep inelastic scattering using a 160 GeV posit…

Spin alignment and violation of the OZI rule in exclusive $I ¨ $ and $I ¨ $ production in pp collisions

C. Adolph, R. Akhunzyanov, M. G. Alexeev +206

Exclusive production of the isoscalar vector mesons $I ¨ $ and $I ¨ $ is measured with a 190 GeV $/ c$ proton beam impinging on a liquid hydrogen target. Cross section ratios are determi…

First measurement of the Sivers asymmetry for gluons from SIDIS data

C. Adolph, M. Aghasyan, R. Akhunzyanov +223

The Sivers function describes the correlation between the transverse spin of a nucleon and the transverse motion of its partons. It was extracted from measurements of the azimuthal…

Hadron Transverse Momentum Distributions in Muon Deep Inelastic Scattering at 160 GeV/ $c$

C. Adolph, M. G. Alekseev, V. Yu. Alexakhin +207

Multiplicities of charged hadrons produced in deep inelastic muon scattering off a $^{6}$ LiD target have been measured as a function of the DIS variables $x_{B j}$ , $Q^{2}$ , $W^{2}$ and t…