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Report number arXiv:1702.06315
Title The $t$-dependence of the pure DVCS cross section at COMPASS
Related titleThe $t$-dependence of the pure DVCS cross section at COMPASS
Author(s) Joerg, Philipp (Freiburg U.)
Collaboration COMPASS Collaboration
Publication SISSA, 2016-10-10
Imprint 2017-02-21
Number of pages 7
Note Conference proceeding to the XXIV International Workshop on Deep-Inelastic Scattering and Related Subjects
In: PoS DIS2016 (2016) 235
In: 24th International Workshop on Deep Inelastic Scattering and related subjects, Hamburg, Germany, 11 - 15 Apr 2016, pp.235
DOI 10.22323/1.265.0235
Subject category nucl-ex ; Nuclear Physics - Experiment ; hep-ex ; Particle Physics - Experiment
Accelerator/Facility, Experiment CERN SPS ; COMPASS NA58
Abstract The key reactions to study the Generalised Parton Distributions are Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP). At COMPASS, these processes are investigated using a high intensity muon beam with a momentum of 160\,GeV/c and a 2.5\,m-long liquid hydrogen target. In order to optimize the selection of exclusive reactions at these energies, the target is surrounded by a new barrel-shaped time-of-flight system to detect the recoiling particles. COMPASS-II covers the up to now unexplored $x_{B}$ domain ranging from 0.01 to 0.15. From the sum of cross sections measured with positive and negative beam polarities, the pure DVCS cross-section and its $t$-dependence have been extracted resulting in a first model-independent determination of the transverse size of the partonic distribution of the nucleon $\sqrt{<r_{\perp}^2>}= (0.578 \ \pm \ 0.042\ _{- \ 0.018}^{+ \ 0.006})\,\textsf{fm} $ at a mean $x_{B}$ value of 0.056.
Copyright/License arXiv nonexclusive-distrib. 1.0
publication: (License: CC-BY-NC-SA)



Corresponding record in: Inspire


 Record created 2017-02-25, last modified 2021-09-16


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Download fulltext00007 COMPASS results for the t-slope parameter (\textbf{left}) and the extracted transverse size of the partonic distribution of the nucleon (\textbf{right}), compared with previous HERA measurements.
Download fulltext00003 Exclusivity variables: The whole Monte Carlo estimate is shown in red while in grey only the $\pi^0$ contamination is shown. The variables $\Delta \varphi$, $\Delta p_{\bot}$ and $M_X^2$ are defined in equation \ref{eq_phi}-\ref{eq_m} while $\Delta z_{A}$ encodes a reverse vertex pointing. The blue dotted lines indicate the applied cuts.
Download fulltext00006 COMPASS results for the t-slope parameter (\textbf{left}) and the extracted transverse size of the partonic distribution of the nucleon (\textbf{right}), compared with previous HERA measurements.
Download fulltext00001 Exclusivity variables: The whole Monte Carlo estimate is shown in red while in grey only the $\pi^0$ contamination is shown. The variables $\Delta \varphi$, $\Delta p_{\bot}$ and $M_X^2$ are defined in equation \ref{eq_phi}-\ref{eq_m} while $\Delta z_{A}$ encodes a reverse vertex pointing. The blue dotted lines indicate the applied cuts.
Download fulltext00002 Exclusivity variables: The whole Monte Carlo estimate is shown in red while in grey only the $\pi^0$ contamination is shown. The variables $\Delta \varphi$, $\Delta p_{\bot}$ and $M_X^2$ are defined in equation \ref{eq_phi}-\ref{eq_m} while $\Delta z_{A}$ encodes a reverse vertex pointing. The blue dotted lines indicate the applied cuts.
Download fulltext00000 Exclusivity variables: The whole Monte Carlo estimate is shown in red while in grey only the $\pi^0$ contamination is shown. The variables $\Delta \varphi$, $\Delta p_{\bot}$ and $M_X^2$ are defined in equation \ref{eq_phi}-\ref{eq_m} while $\Delta z_{A}$ encodes a reverse vertex pointing. The blue dotted lines indicate the applied cuts.
Download fulltext00005 The $t$-differential DVCS cross section as a function of $t$
Download fulltext00004 Acceptance correction factors as a function of $t$, $Q^2$ and $\nu$.
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