English
Related papers

Related papers: Hard exclusive processes in the backward region

200 papers

Hard exclusive electroproduction of kaons as well as the kaon-induced exclusive Drell-Yan process are investigated within the handbag approach which is based on factorization in hard subprocesses and soft generalized parton distributions…

High Energy Physics - Phenomenology · Physics 2025-01-03 P. Kroll

Exclusive $\gamma\gamma \to$ hadron pairs are among the most fundamental processes in QCD, providing a detailed examination of Compton scattering in the crossed channel. In the high momentum transfer domain $(s,t, {large},\theta_{cm}$ for…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. J. Brodsky

We review our results on a new class of $2 \to 3$ exclusive processes, as a probe of both chiral-even and chiral-odd quark GPDs. We consider the exclusive photoproduction of a photon-meson pair, in the kinematics where the pair has a large…

High Energy Physics - Phenomenology · Physics 2024-10-08 Goran Duplančić , Saad Nabeebaccus , Kornelija Passek-K. , Bernard Pire , Lech Szymanowski , Samuel Wallon

In this talk it is reported on an analysis of hard exclusive leptoproduction of pions within the handbag approach. It is argued that recent measurements of this process performed by HERMES and CLAS clearly indicate the occurrence of strong…

High Energy Physics - Phenomenology · Physics 2025-01-03 Peter Kroll

We propose to describe the process $ p ~ \bar{p} \rightarrow \pi^+ ~ \pi^-$ in a perturbative, QCD motivated framework in which a hard $ud \, \bar{u} \bar{d} \rightarrow d \, \bar{d} $ annihilation factorizes from soft transition…

High Energy Physics - Phenomenology · Physics 2015-06-17 Alexander T. Goritschnig , Stefan Kofler , Wolfgang Schweiger

Mesons' internal structure and dynamics may be accessed through hard exclusive electroproduction processes such as deeply virtual Compton scattering in both near forward and near backward kinematics. With the help of the Sullivan process…

High Energy Physics - Phenomenology · Physics 2025-04-04 Abigail R. Castro , Cédric Mezrag , Jose M. Morgado Chávez , Bernard Pire

We evaluate the cross section for anti-p p -> l+ l- pi0 in the forward direction and for large lepton pair invariant mass. In this kinematical region, the leading-twist amplitude factorises into a short-distance matrix element,…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. P. Lansberg , B. Pire , L. Szymanowski

Exclusive hadronic reactions with a massive lepton pair (l^+l^-) in the final state will be measured with PANDA at GSI-FAIR and with Compass at CERN, both in p+p-bar -> l^+l^-+pi and pi+N -> N'+l^+l^-. Similarly, electroproduction of a…

High Energy Physics - Phenomenology · Physics 2015-05-20 J. P. Lansberg , B. Pire , L. Szymanowski

Recent analyses of backward meson electroproduction support the validity of a collinear QCD factorization framework for these hard exclusive reactions. This opens a way to the extraction of nucleon-to-meson transition distribution…

High Energy Physics - Phenomenology · Physics 2019-12-13 Bernard Pire , Kirill Semenov-Tian-Shansky , Lech Szymanowski

To study cross sections and polarization asymmetries for the processes $e p \to e n \pi^+$ and $e p \to e p \pi^0$ in the backward region, we develop a flexible phenomenological model for nucleon-to-pion transition distribution amplitudes…

High Energy Physics - Phenomenology · Physics 2025-11-03 Bernard Pire , Kirill Semenov-Tian-Shansky , Paweł Sznajder , Lech Szymanowski

Generalized Parton Distributions offer a new way to access the quark and gluon nucleon structure. We review recent progress in this domain, emphasizing the need to supplement the experimental study of DVCS by its crossed version, timelike…

High Energy Physics - Phenomenology · Physics 2011-09-27 B. Pire , K. Semenov-Tian-Shansky , L. Szymanowski , J. Wagner

We define and study hard ``semi-exclusive'' processes of the form $A+B \to C + Y$ which are characterized by a large momentum transfer between the particles $A$ and $C$ and a large rapidity gap between the final state particle $C$ and the…

High Energy Physics - Phenomenology · Physics 2009-09-11 S. J. Brodsky , M. Diehl , P. Hoyer , S. Peigne

In this talk it is reported on an analysis of hard exclusive electroproduction of pseudoscalar mesons within the handbag approach. It is argued that recent measurements of pion electroproduction performed by HERMES and CLAS clearly indicate…

High Energy Physics - Phenomenology · Physics 2025-01-09 P. Kroll

Hard semiexclusive processes provide an opportunity to design effective currents to probe specific parton distributions and to probe in leading order parton distributions that fully inclusive reactions probe only via higher order…

High Energy Physics - Phenomenology · Physics 2010-12-13 Carl E. Carlson

We calculate the differential cross section and single-polarization observables for the reaction $\gamma p \to \Phi p$ within perturbative QCD, treating the proton as a quark-diquark system. The phenomenological couplings of gauge bosons to…

High Energy Physics - Phenomenology · Physics 2009-10-31 C. F. Berger , W. Schweiger

The proposed measurement is a dedicated study to investigate the exclusive electroproduction process: 1H(e, e'p)X, in the backward angle above the resonance region. Here, the produced particle X (pi0 or gamma) is emitted 180 degrees…

Nuclear Experiment · Physics 2022-05-31 W. B. Li , J. R. Stevens , G. M. Huber

We investigate the hard exclusive photoproduction of photon-meson pairs at leading-twist and leading-order in perturbative QCD, and focus on pseudoscalar mesons $\text{M} \in \{\pi^\pm, \pi^0, \eta, \eta'\}$. Compact analytical expressions…

High Energy Physics - Phenomenology · Physics 2025-11-26 Nikola Crnković , Goran Duplančić , Saad Nabeebaccus , Kornelija Passek-K. , Bernard Pire , Lech Szymanowski , Samuel Wallon

Hard hadronic exclusive processes are now at the forefront of QCD studies, particularly because of their role in the interpretation of exclusive hadronic B decays. Perturbative QCD and its factorization properties at high momentum transfer…

High Energy Physics - Phenomenology · Physics 2017-08-23 Stanley J. Brodsky

We study the hard exclusive production of two pions in the virtual photon fragmentation region with various invariant masses including the resonance region. The amplitude is expressed in terms of two-pion light cone distribution amplitudes…

High Energy Physics - Phenomenology · Physics 2011-04-15 M. V. Polyakov

We show that exclusive production of a pair of high transverse momentum photons in pion-nucleon collisions can be systematically studied in QCD factorization approach if the photon's transverse momentum $q_T$ with respect to the colliding…

High Energy Physics - Phenomenology · Physics 2022-08-24 Jian-Wei Qiu , Zhite Yu