Related papers: Studies of TMDs at COMPASS

Transverse momentum distributions of quarks in the nucleon from Lattice QCD

Transverse momentum dependent parton distribution functions (TMDPDFs) encode information about the intrinsic motion of quarks inside the nucleon. They are important non-perturbative ingredients in our understanding of, e.g., azimuthal…

High Energy Physics - Lattice · Physics 2008-11-11 Bernhard U. Musch , Philipp Hägler , Andreas Schäfer , Dru B. Renner , John W. Negele , LHPC Collaboration

Longitudinal double spin asymmetry $A_1^p$ and spin-dependent structure function $g_1^p$ of the proton at low $x$ and low $Q^2$ from COMPASS

The COMPASS experiment at CERN has collected a large sample of events of inelastic scattering of longitudinally polarised muons off longitudinally polarised protons in the non-perturbative region (four-momentum transfer squared $Q^2<1$…

High Energy Physics - Experiment · Physics 2019-08-13 A. S. Nunes

Recent Physics results with the COMPASS Experiment

The COMPASS experiment has obtained first physics results in the field of polarized distribution functions for quarks and gluons using muon scattering off polarized deuterons. The analysis using open charm production and pairs of high $p_T$…

High Energy Physics - Experiment · Physics 2009-11-11 Stephan Paul

Nucleon Spin Structure with hadronic collisions at COMPASS

In order to illustrate the capabilities of COMPASS using a hadronic beam, I review some of the azimuthal asymmetries in hadronic collisions, that allow for the extraction of transversity, Sivers and Boer-Mulders functions, necessary to…

High Energy Physics - Phenomenology · Physics 2007-08-03 Marco Radici , Francesco Conti , Alessandro Bacchetta , Andrea Bianconi

Transversity studies with protons and light nuclei

A general formalism to evaluate time-reversal odd transverse momentum dependent parton distributions (T-odd TMDS) is reviewed and applied to the calculation of the leading-twist quantities, i.e., the Sivers and the Boer-Mulders functions.…

High Energy Physics - Phenomenology · Physics 2015-05-30 Sergio Scopetta

First simultaneous analysis of transverse momentum dependent and collinear parton distributions in the proton

We present the first simultaneous global QCD analysis of unpolarized transverse momentum dependent (TMD) and collinear parton distribution functions (PDFs) in the proton. Our study incorporates data from deep-inelastic scattering,…

High Energy Physics - Phenomenology · Physics 2025-10-16 P. C. Barry , A. Prokudin , T. Anderson , C. Cocuzza , L. Gamberg , W. Melnitchouk , E. Moffat , D. Pitonyak , J. -W. Qiu , N. Sato , A. Vladimirov , R. M. Whitehill

Transverse (Spin) Structure of Hadrons

Parton distributions in impact parameter space, which are obtained by Fourier transforming GPDs, exhibit a significant deviation from axial symmetry when the target and/or quark are transversely polarized. Connections between this…

High Energy Physics - Phenomenology · Physics 2017-02-01 Matthias Burkardt

Transverse Momentum Dependent Partonic Distribution and Fragmentation Functions

Our knowledge on the three-dimensional momentum structure of hadrons is encoded in the Transverse Momentum Dependent partonic distribution and fragmentation functions (TMDs). A brief and updated review of the TMDs and of the processes in…

High Energy Physics - Phenomenology · Physics 2015-05-30 M. Boglione

Nucleon spin densities in a light-front constituent quark model

The first moment of longitudinal and transverse spin densities of quarks in the nucleon are calculated in a light-front constituent quark model for the different cases of quark and nucleon polarization. Significant distortions are found for…

High Energy Physics - Phenomenology · Physics 2008-11-26 B. Pasquini , S. Boffi

Future Programme of COMPASS at CERN

COMPASS at CERN is preparing for a new series of measurements on the nucleon structure comprising deep virtual Compton scattering and hard exclusive meson production using muon beams, as well as Drell-Yan reactions using a polarised proton…

High Energy Physics - Experiment · Physics 2012-06-14 Gerhard K. Mallot

Unveiling the proton structure via transverse-momentum-dependent gluon distributions

We present exploratory studies of the proton content via unpolarized and polarized transverse-momentum-dependent gluon distributions in the proton at leading twist. We make use of an enhanced spectator-model approach to encode in our…

High Energy Physics - Phenomenology · Physics 2022-06-17 Alessandro Bacchetta , Francesco Giovanni Celiberto , Marco Radici

Transverse spin-dependent azimuthal correlations of charged pion pairs measured in p$^\uparrow$+p collisions at $\sqrt{s}$ = 500 GeV

The transversity distribution, which describes transversely polarized quarks in transversely polarized nucleons, is a fundamental component of the spin structure of the nucleon, and is only loosely constrained by global fits to existing…

High Energy Physics - Experiment · Physics 2018-03-16 STAR Collaboration , L. Adamczyk , J. R. Adams , J. K. Adkins , G. Agakishiev , M. M. Aggarwal , Z. Ahammed , N. N. Ajitanand , I. Alekseev , D. M. Anderson , R. Aoyama , A. Aparin , D. Arkhipkin , E. C. Aschenauer , M. U. Ashraf , A. Attri , G. S. Averichev , X. Bai , V. Bairathi , K. Barish , A. Behera , R. Bellwied , A. Bhasin , A. K. Bhati , P. Bhattarai , J. Bielcik , J. Bielcikova , L. C. Bland , I. G. Bordyuzhin , J. Bouchet , J. D. Brandenburg , A. V. Brandin , D. Brown , J. Bryslawskyj , I. Bunzarov , J. Butterworth , H. Caines , M. Calderón de la Barca Sánchez , J. M. Campbell , D. Cebra , I. Chakaberia , P. Chaloupka , Z. Chang , N. Chankova-Bunzarova , A. Chatterjee , S. Chattopadhyay , X. Chen , J. H. Chen , X. Chen , J. Cheng , M. Cherney , W. Christie , G. Contin , H. J. Crawford , S. Das , T. G. Dedovich , J. Deng , I. M. Deppner , A. A. Derevschikov , L. Didenko , C. Dilks , X. Dong , J. L. Drachenberg , J. E. Draper , J. C. Dunlop , L. G. Efimov , N. Elsey , J. Engelage , G. Eppley , R. Esha , S. Esumi , O. Evdokimov , J. Ewigleben , O. Eyser , R. Fatemi , S. Fazio , P. Federic , P. Federicova , J. Fedorisin , Z. Feng , P. Filip , E. Finch , Y. Fisyak , C. E. Flores , J. Fujita , L. Fulek , C. A. Gagliardi , F. Geurts , A. Gibson , M. Girard , D. Grosnick , D. S. Gunarathne , Y. Guo , A. Gupta , W. Guryn , A. I. Hamad , A. Hamed , A. Harlenderova , J. W. Harris , L. He , S. Heppelmann , S. Heppelmann , N. Herrmann , A. Hirsch , S. Horvat , X. Huang , H. Z. Huang , T. Huang , B. Huang , T. J. Humanic , P. Huo , G. Igo , W. W. Jacobs , A. Jentsch , J. Jia , K. Jiang , S. Jowzaee , E. G. Judd , S. Kabana , D. Kalinkin , K. Kang , D. Kapukchyan , K. Kauder , H. W. Ke , D. Keane , A. Kechechyan , Z. Khan , D. P. Kikoła , C. Kim , I. Kisel , A. Kisiel , L. Kochenda , M. Kocmanek , T. Kollegger , L. K. Kosarzewski , A. F. Kraishan , L. Krauth , P. Kravtsov , K. Krueger , N. Kulathunga , L. Kumar , J. Kvapil , J. H. Kwasizur , R. Lacey , J. M. Landgraf , K. D. Landry , J. Lauret , A. Lebedev , R. Lednicky , J. H. Lee , W. Li , C. Li , X. Li , Y. Li , J. Lidrych , T. Lin , M. A. Lisa , F. Liu , P. Liu , Y. Liu , H. Liu , T. Ljubicic , W. J. Llope , M. Lomnitz , R. S. Longacre , S. Luo , X. Luo , G. L. Ma , R. Ma , Y. G. Ma , L. Ma , N. Magdy , R. Majka , D. Mallick , S. Margetis , C. Markert , H. S. Matis , D. Mayes , K. Meehan , J. C. Mei , Z. W. Miller , N. G. Minaev , S. Mioduszewski , D. Mishra , S. Mizuno , B. Mohanty , M. M. Mondal , D. A. Morozov , M. K. Mustafa , Md. Nasim , T. K. Nayak , J. M. Nelson , D. B. Nemes , M. Nie , G. Nigmatkulov , T. Niida , L. V. Nogach , T. Nonaka , S. B. Nurushev , G. Odyniec , A. Ogawa , K. Oh , V. A. Okorokov , D. Olvitt , B. S. Page , R. Pak , Y. Pandit , Y. Panebratsev , B. Pawlik , H. Pei , C. Perkins , J. Pluta , K. Poniatowska , J. Porter , M. Posik , N. K. Pruthi , M. Przybycien , J. Putschke , A. Quintero , S. Ramachandran , R. L. Ray , R. Reed , M. J. Rehbein , H. G. Ritter , J. B. Roberts , O. V. Rogachevskiy , J. L. Romero , J. D. Roth , L. Ruan , J. Rusnak , O. Rusnakova , N. R. Sahoo , P. K. Sahu , S. Salur , J. Sandweiss , M. Saur , J. Schambach , A. M. Schmah , W. B. Schmidke , N. Schmitz , B. R. Schweid , J. Seger , M. Sergeeva , R. Seto , P. Seyboth , N. Shah , E. Shahaliev , P. V. Shanmuganathan , M. Shao , W. Q. Shen , S. S. Shi , Z. Shi , Q. Y. Shou , E. P. Sichtermann , R. Sikora , M. Simko , S. Singha , M. J. Skoby , N. Smirnov , D. Smirnov , W. Solyst , P. Sorensen , H. M. Spinka , B. Srivastava , T. D. S. Stanislaus , D. J. Stewart , M. Strikhanov , B. Stringfellow , A. A. P. Suaide , T. Sugiura , M. Sumbera , B. Summa , X. Sun , Y. Sun , X. M. Sun , B. Surrow , D. N. Svirida , Z. Tang , A. H. Tang , A. Taranenko , T. Tarnowsky , A. Tawfik , J. Thäder , J. H. Thomas , A. R. Timmins , D. Tlusty , T. Todoroki , M. Tokarev , S. Trentalange , R. E. Tribble , P. Tribedy , S. K. Tripathy , B. A. Trzeciak , O. D. Tsai , B. Tu , T. Ullrich , D. G. Underwood , I. Upsal , G. Van Buren , G. van Nieuwenhuizen , A. N. Vasiliev , F. Videbæk , S. Vokal , S. A. Voloshin , A. Vossen , G. Wang , F. Wang , Y. Wang , Y. Wang , G. Webb , J. C. Webb , L. Wen , G. D. Westfall , H. Wieman , S. W. Wissink , R. Witt , Y. Wu , Z. G. Xiao , G. Xie , W. Xie , Q. H. Xu , Y. F. Xu , J. Xu , N. Xu , Z. Xu , C. Yang , S. Yang , Q. Yang , Y. Yang , Z. Ye , Z. Ye , L. Yi , K. Yip , I. -K. Yoo , N. Yu , H. Zbroszczyk , W. Zha , J. B. Zhang , J. Zhang , S. Zhang , L. Zhang , J. Zhang , X. P. Zhang , Z. Zhang , S. Zhang , Y. Zhang , J. Zhao , C. Zhong , C. Zhou , L. Zhou , X. Zhu , Z. Zhu , M. Zyzak

Structure Functions

Recent progress in the understanding of the nucleon is presented. The unpolarised structure functions are obtained with unprecedented precision from the combined H1 and ZEUS data and are used to extract proton parton distribution functions…

High Energy Physics - Experiment · Physics 2009-03-27 Cristinel Diaconu

TMDs and Azimuthal Spin Asymmetries in a Light-Cone Quark Model

The main properties of the leading-twist transverse momentum dependent parton distributions in a light-cone constituent quark model of the nucleon are reviewed, with focus on the role of the spin-spin and spin-orbit correlations of quarks.…

High Energy Physics - Phenomenology · Physics 2009-08-24 B. Pasquini , S. Boffi , A. V. Efremov , P. Schweitzer

Light-front transverse charge densities

We discuss the recent interpretation of quark-distribution functions in the plane transverse to the light-cone direction. Such a mapping is model independent and allows one to build up multidimensional pictures of the hadron and to develop…

High Energy Physics - Phenomenology · Physics 2015-05-20 Cédric Lorcé , Barbara Pasquini , Marc Vanderhaeghen

Comparative Analysis of Transversities and Longitudinally Polarized Distributions of the Nucleon

We carry out a comparative analysis of the transversities and the longitudinally polarized parton distribution functions in light of the first empirical extraction of the transversity distributions recently done by Anselmino et al. It is…

High Energy Physics - Phenomenology · Physics 2007-11-29 M. Wakamatsu

Unpolarised Transverse Momentum Dependent Distribution and Fragmentation Functions from SIDIS Multiplicities

The unpolarised transverse momentum dependent distribution and fragmentation functions are extracted from HERMES and COMPASS experimental measurements of SIDIS multiplicities for charged hadron production. The data are grouped into…

High Energy Physics - Phenomenology · Physics 2015-06-18 M. Anselmino , M. Boglione , J. O. Gonzalez H. , S. Melis , A. Prokudin

Generalized Parton Distributions and Transversity in Nucleons and Nuclei

We present an exploratory study using generalized parton distributions of several observables related to transverse degrees of freedom in hadronic structure -- the nucleon transverse momentum, the transverse radius, or impact parameter, and…

High Energy Physics - Phenomenology · Physics 2009-11-11 S. Liuti

Weighted transverse spin asymmetries in 2015 COMPASS Drell-Yan data

Muon pairs created in the Drell-Yan process of a negative pion beam of 190 GeV/c momentum impinging on a transversely polarised NH$_3$ target were detected with the COMPASS spectrometer at CERN in 2015. In addition to the extraction of the…

High Energy Physics - Experiment · Physics 2018-12-21 Jan Matousek

Exclusive rho^0 muoproduction on transversely polarised protons and deuterons

The transverse target spin azimuthal asymmetry A_UT in hard exclusive production of rho^0 mesons was measured at COMPASS by scattering 160 GeV/c muons off transversely polarised protons and deuterons. The measured asymmetry is sensitive to…

High Energy Physics - Experiment · Physics 2015-06-05 C. Adolph , M. G. Alekseev , V. Yu. Alexakhin , Yu. Alexandrov , G. D. Alexeev , A. Amoroso , A. A. Antonov , A. Austregesilo , B. Badełek , F. Balestra , J. Barth , G. Baum , Y. Bedfer , J. Bernhard , R. Bertini , M. Bettinelli , K. Bicker , J. Bieling , R. Birsa , J. Bisplinghoff , P. Bordalo , F. Bradamante , C. Braun , A. Bravar , A. Bressan , M. Büchele , E. Burtin , L. Capozza , M. Chiosso , S. U. Chung , A. Cicuttin , M. L. Crespo , S. Dalla Torre , S. Das , S. S. Dasgupta , S. Dasgupta , O. Yu. Denisov , L. Dhara , S. V. Donskov , N. Doshita , V. Duic , W. Dünnweber , M. Dziewiecki , A. Efremov , C. Elia , P. D. Eversheim , W. Eyrich , M. Faessler , A. Ferrero , A. Filin , M. Finger , M. Finger , H. Fischer , C. Franco , N. du Fresne von Hohenesche , J. M. Friedrich , V. Frolov , R. Garfagnini , F. Gautheron , O. P. Gavrichtchouk , S. Gerassimov , R. Geyer , M. Giorgi , I. Gnesi , B. Gobbo , S. Goertz , S. Grabmüller , A. Grasso , B. Grube , R. Gushterski , A. Guskov , T. Guthörl , F. Haas , D. von Harrach , F. H. Heinsius , F. Herrmann , C. Heß , F. Hinterberger , N. Horikawa , Ch. Höppner , N. d'Hose , S. Ishimoto , O. Ivanov , Yu. Ivanshin , T. Iwata , R. Jahn , V. Jary , P. Jasinski , G. Jegou , R. Joosten , E. Kabuß , D. Kang , B. Ketzer , G. V. Khaustov , Yu. A. Khokhlov , Yu. Kisselev , F. Klein , K. Klimaszewski , S. Koblitz , J. H. Koivuniemi , V. N. Kolosov , K. Kondo , K. Königsmann , I. Konorov , V. F. Konstantinov , A. Korzenev , A. M. Kotzinian , O. Kouznetsov , M. Krämer , Z. V. Kroumchtein , F. Kunne , K. Kurek , L. Lauser , A. A. Lednev , A. Lehmann , S. Levorato , J. Lichtenstadt , T. Liska , A. Maggiora , A. Magnon , N. Makke , G. K. Mallot , A. Mann , C. Marchand , A. Martin , J. Marzec , T. Matsuda , G. Meshcheryakov , W. Meyer , T. Michigami , Yu. V. Mikhailov , M. A. Moinester , A. Morreale , A. Mutter , A. Nagaytsev , T. Nagel , T. Negrini , F. Nerling , S. Neubert , D. Neyret , V. I. Nikolaenko , W. -D. Nowak , A. S. Nunes , A. G. Olshevsky , M. Ostrick , A. Padee , R. Panknin , D. Panzieri , B. Parsamyan , S. Paul , E. Perevalova , G. Pesaro , D. V. Peshekhonov , G. Piragino , S. Platchkov , J. Pochodzalla , J. Polak , V. A. Polyakov , J. Pretz , M. Quaresma , C. Quintans , J. -F. Rajotte , S. Ramos , V. Rapatsky , G. Reicherz , A. Richter , E. Rocco , E. Rondio , N. S. Rossiyskaya , D. I. Ryabchikov , V. D. Samoylenko , A. Sandacz , M. G. Sapozhnikov , S. Sarkar , I. A. Savin , G. Sbrizzai , P. Schiavon , C. Schill , T. Schlüter , K. Schmidt , L. Schmitt , K. Schönning , S. Schopferer , M. Schott , W. Schröder , O. Yu. Shevchenko , L. Silva , L. Sinha , A. N. Sissakian , M. Slunecka , G. I. Smirnov , S. Sosio , F. Sozzi , A. Srnka , L. Steiger , M. Stolarski , M. Sulc , R. Sulej , H. Suzuki , P. Sznajder , S. Takekawa , J. Ter Wolbeek , S. Tessaro , F. Tessarotto , L. G. Tkatchev , S. Uhl , I. Uman , M. Vandenbroucke , M. Virius , N. V. Vlassov , L. Wang , M. Wilfert , R. Windmolders , W. Wiślicki , H. Wollny , K. Zaremba , M. Zavertyaev , E. Zemlyanichkina , M. Ziembicki , N. Zhuravlev , A. Zvyagin