Related papers: e^+e^- Pair Production from $\gamma$ A Reactions

Measurement of $\Sigma^+$ transverse polarization in $e^+e^-$ collisions at $\sqrt{s} = 3.68-3.71$ GeV

Using $e^+e^-$ collision data collected with the BESIII detector at seven energy points ranging from 3.68 to 3.71 GeV and corresponding to an integrated luminosity of $652.1~{\rm pb^{-1}}$, we present an energy-dependent measurement of the…

High Energy Physics - Experiment · Physics 2024-12-31 BESIII Collaboration , M. Ablikim , M. N. Achasov , P. Adlarson , O. Afedulidis , X. C. Ai , R. Aliberti , A. Amoroso , Q. An , Y. Bai , O. Bakina , I. Balossino , Y. Ban , H. -R. Bao , V. Batozskaya , K. Begzsuren , N. Berger , M. Berlowski , M. Bertani , D. Bettoni , F. Bianchi , E. Bianco , A. Bortone , I. Boyko , R. A. Briere , A. Brueggemann , H. Cai , X. Cai , A. Calcaterra , G. F. Cao , N. Cao , S. A. Cetin , J. F. Chang , G. R. Che , G. Chelkov , C. Chen , C. H. Chen , Chao Chen , G. Chen , H. S. Chen , H. Y. Chen , M. L. Chen , S. J. Chen , S. L. Chen , S. M. Chen , T. Chen , X. R. Chen , X. T. Chen , Y. B. Chen , Y. Q. Chen , Z. J. Chen , Z. Y. Chen , S. K. Choi , G. Cibinetto , F. Cossio , J. J. Cui , H. L. Dai , J. P. Dai , A. Dbeyssi , R. E. de Boer , D. Dedovich , C. Q. Deng , Z. Y. Deng , A. Denig , I. Denysenko , M. Destefanis , F. De Mori , B. Ding , X. X. Ding , Y. Ding , Y. Ding , J. Dong , L. Y. Dong , M. Y. Dong , X. Dong , M. C. Du , S. X. Du , Y. Y. Duan , Z. H. Duan , P. Egorov , Y. H. Fan , J. Fang , J. Fang , S. S. Fang , W. X. Fang , Y. Fang , Y. Q. Fang , R. Farinelli , L. Fava , F. Feldbauer , G. Felici , C. Q. Feng , J. H. Feng , Y. T. Feng , M. Fritsch , C. D. Fu , J. L. Fu , Y. W. Fu , H. Gao , X. B. Gao , Y. N. Gao , Yang Gao , S. Garbolino , I. Garzia , L. Ge , P. T. Ge , Z. W. Ge , C. Geng , E. M. Gersabeck , A. Gilman , K. Goetzen , L. Gong , W. X. Gong , W. Gradl , S. Gramigna , M. Greco , M. H. Gu , Y. T. Gu , C. Y. Guan , A. Q. Guo , L. B. Guo , M. J. Guo , R. P. Guo , Y. P. Guo , A. Guskov , J. Gutierrez , K. L. Han , T. T. Han , F. Hanisch , X. Q. Hao , F. A. Harris , K. K. He , K. L. He , F. H. Heinsius , C. H. Heinz , Y. K. Heng , C. Herold , T. Holtmann , P. C. Hong , G. Y. Hou , X. T. Hou , Y. R. Hou , Z. L. Hou , B. Y. Hu , H. M. Hu , J. F. Hu , S. L. Hu , T. Hu , Y. Hu , G. S. Huang , K. X. Huang , L. Q. Huang , X. T. Huang , Y. P. Huang , Y. S. Huang , T. Hussain , F. H\ölzken , N. H\üsken , N. in der Wiesche , J. Jackson , S. Janchiv , J. H. Jeong , Q. Ji , Q. P. Ji , W. Ji , X. B. Ji , X. L. Ji , Y. Y. Ji , X. Q. Jia , Z. K. Jia , D. Jiang , H. B. Jiang , P. C. Jiang , S. S. Jiang , T. J. Jiang , X. S. Jiang , Y. Jiang , J. B. Jiao , J. K. Jiao , Z. Jiao , S. Jin , Y. Jin , M. Q. Jing , X. M. Jing , T. Johansson , S. Kabana , N. Kalantar-Nayestanaki , X. L. Kang , X. S. Kang , M. Kavatsyuk , B. C. Ke , V. Khachatryan , A. Khoukaz , R. Kiuchi , O. B. Kolcu , B. Kopf , M. Kuessner , X. Kui , N. Kumar , A. Kupsc , W. K\ühn , J. J. Lane , P. Larin , L. Lavezzi , T. T. Lei , Z. H. Lei , M. Lellmann , T. Lenz , C. Li , C. Li , C. H. Li , Cheng Li , D. M. Li , F. Li , G. Li , H. B. Li , H. J. Li , H. N. Li , Hui Li , J. R. Li , J. S. Li , K. Li , L. J. Li , L. K. Li , Lei Li , M. H. Li , P. R. Li , Q. M. Li , Q. X. Li , R. Li , S. X. Li , T. Li , W. D. Li , W. G. Li , X. Li , X. H. Li , X. L. Li , X. Y. Li , X. Z. Li , Y. G. Li , Z. J. Li , Z. Y. Li , C. Liang , H. Liang , H. Liang , Y. F. Liang , Y. T. Liang , G. R. Liao , L. Z. Liao , Y. P. Liao , J. Libby , A. Limphirat , C. C. Lin , D. X. Lin , T. Lin , B. J. Liu , B. X. Liu , C. Liu , C. X. Liu , F. Liu , F. H. Liu , Feng Liu , G. M. Liu , H. Liu , H. B. Liu , H. H. Liu , H. M. Liu , Huihui Liu , J. B. Liu , J. Y. Liu , K. Liu , K. Y. Liu , Ke Liu , L. Liu , L. C. Liu , Lu Liu , M. H. Liu , P. L. Liu , Q. Liu , S. B. Liu , T. Liu , W. K. Liu , W. M. Liu , X. Liu , X. Liu , Y. Liu , Y. Liu , Y. B. Liu , Z. A. Liu , Z. D. Liu , Z. Q. Liu , X. C. Lou , F. X. Lu , H. J. Lu , J. G. Lu , X. L. Lu , Y. Lu , Y. P. Lu , Z. H. Lu , C. L. Luo , J. R. Luo , M. X. Luo , T. Luo , X. L. Luo , X. R. Lyu , Y. F. Lyu , F. C. Ma , H. Ma , H. L. Ma , J. L. Ma , L. L. Ma , M. M. Ma , Q. M. Ma , R. Q. Ma , T. Ma , X. T. Ma , X. Y. Ma , Y. Ma , Y. M. Ma , F. E. Maas , M. Maggiora , S. Malde , Y. J. Mao , Z. P. Mao , S. Marcello , Z. X. Meng , J. G. Messchendorp , G. Mezzadri , H. Miao , T. J. Min , R. E. Mitchell , X. H. Mo , B. Moses , N. Yu. Muchnoi , J. Muskalla , Y. Nefedov , F. Nerling , L. S. Nie , I. B. Nikolaev , Z. Ning , S. Nisar , Q. L. Niu , W. D. Niu , Y. Niu , S. L. Olsen , Q. Ouyang , S. Pacetti , X. Pan , Y. Pan , A. Pathak , P. Patteri , Y. P. Pei , M. Pelizaeus , H. P. Peng , Y. Y. Peng , K. Peters , J. L. Ping , R. G. Ping , S. Plura , V. Prasad , F. Z. Qi , H. Qi , H. R. Qi , M. Qi , T. Y. Qi , S. Qian , W. B. Qian , C. F. Qiao , X. K. Qiao , J. J. Qin , L. Q. Qin , L. Y. Qin , X. P. Qin , X. S. Qin , Z. H. Qin , J. F. Qiu , Z. H. Qu , C. F. Redmer , K. J. Ren , A. Rivetti , M. Rolo , G. Rong , Ch. Rosner , S. N. Ruan , N. Salone , A. Sarantsev , Y. Schelhaas , K. Schoenning , M. Scodeggio , K. Y. Shan , W. Shan , X. Y. Shan , Z. J. Shang , J. F. Shangguan , L. G. Shao , M. Shao , C. P. Shen , H. F. Shen , W. H. Shen , X. Y. Shen , B. A. Shi , H. Shi , H. C. Shi , J. L. Shi , J. Y. Shi , Q. Q. Shi , S. Y. Shi , X. Shi , J. J. Song , T. Z. Song , W. M. Song , Y. J. Song , Y. X. Song , S. Sosio , S. Spataro , F. Stieler , Y. J. Su , G. B. Sun , G. X. Sun , H. Sun , H. K. Sun , J. F. Sun , K. Sun , L. Sun , S. S. Sun , T. Sun , W. Y. Sun , Y. Sun , Y. J. Sun , Y. Z. Sun , Z. Q. Sun , Z. T. Sun , C. J. Tang , G. Y. Tang , J. Tang , M. Tang , Y. A. Tang , L. Y. Tao , Q. T. Tao , M. Tat , J. X. Teng , V. Thoren , W. H. Tian , Y. Tian , Z. F. Tian , I. Uman , Y. Wan , S. J. Wang , B. Wang , B. L. Wang , Bo Wang , D. Y. Wang , F. Wang , H. J. Wang , J. J. Wang , J. P. Wang , K. Wang , L. L. Wang , M. Wang , N. Y. Wang , S. Wang , S. Wang , T. Wang , T. J. Wang , W. Wang , W. Wang , W. P. Wang , X. Wang , X. F. Wang , X. J. Wang , X. L. Wang , X. N. Wang , Y. Wang , Y. D. Wang , Y. F. Wang , Y. L. Wang , Y. N. Wang , Y. Q. Wang , Yaqian Wang , Yi Wang , Z. Wang , Z. L. Wang , Z. Y. Wang , Ziyi Wang , D. H. Wei , F. Weidner , S. P. Wen , Y. R. Wen , U. Wiedner , G. Wilkinson , M. Wolke , L. Wollenberg , C. Wu , J. F. Wu , L. H. Wu , L. J. Wu , X. Wu , X. H. Wu , Y. Wu , Y. H. Wu , Y. J. Wu , Z. Wu , L. Xia , X. M. Xian , B. H. Xiang , T. Xiang , D. Xiao , G. Y. Xiao , S. Y. Xiao , Y. L. Xiao , Z. J. Xiao , C. Xie , X. H. Xie , Y. Xie , Y. G. Xie , Y. H. Xie , Z. P. Xie , T. Y. Xing , C. F. Xu , C. J. Xu , G. F. Xu , H. Y. Xu , M. Xu , Q. J. Xu , Q. N. Xu , W. Xu , W. L. Xu , X. P. Xu , Y. C. Xu , Z. P. Xu , Z. S. Xu , F. Yan , L. Yan , W. B. Yan , W. C. Yan , X. Q. Yan , H. J. Yang , H. L. Yang , H. X. Yang , T. Yang , Y. Yang , Y. F. Yang , Y. F. Yang , Y. X. Yang , Z. W. Yang , Z. P. Yao , M. Ye , M. H. Ye , J. H. Yin , Z. Y. You , B. X. Yu , C. X. Yu , G. Yu , J. S. Yu , T. Yu , X. D. Yu , Y. C. Yu , C. Z. Yuan , J. Yuan , J. Yuan , L. Yuan , S. C. Yuan , Y. Yuan , Z. Y. Yuan , C. X. Yue , A. A. Zafar , F. R. Zeng , S. H. Zeng , X. Zeng , Y. Zeng , Y. J. Zeng , Y. J. Zeng , X. Y. Zhai , Y. C. Zhai , Y. H. Zhan , A. Q. Zhang , B. L. Zhang , B. X. Zhang , D. H. Zhang , G. Y. Zhang , H. Zhang , H. Zhang , H. 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C. Zhu , Z. A. Zhu , J. H. Zou , J. Zu

On the two-photon contributions to $e^+e^-\to\eta\gamma$ and $e^+e^-\to\eta^\prime\gamma$

Motivated by recent BABAR measurements of the $\gamma^*\to\gamma \eta$ and $\gamma^*\to\gamma \eta^\prime $ transition form factors, we estimate two-photon exchange contributions to the corresponding cross sections. By using a…

High Energy Physics - Phenomenology · Physics 2008-11-26 Z. K. Silagadze

Dilepton production and resonance properties within a new hadronic transport approach in the context of the GSI-HADES experimental data

The dilepton emission in heavy-ion reactions at low beam energies is examined within a hadronic transport approach. In this article the production of electron-positron pairs from a new approach named SMASH (Simulating Many Accelerated…

Nuclear Theory · Physics 2018-12-05 Jan Staudenmaier , Janus Weil , Vinzent Steinberg , Stephan Endres , Hannah Petersen

Predictions for ${\bar \nu} \nu \gamma$ Production at LEP

We study predictions for the reaction $e^+e^- \to {\bar \nu} \nu (n \gamma)$. The complete one-loop corrections are taken into account and higher order contributions, in particular those for the observed real photons, are added whenever…

High Energy Physics - Phenomenology · Physics 2011-09-13 D. Bardin , S. Jadach , T. Riemann , Z. Was

Production of $e^{+}e^{-}$ from U+U collisions at $\sqrt{s_{NN}}$ = 193 GeV and Au+Au collisions at $\sqrt{s_{NN}}$ = 19.6, 27, 39, 62.4, and 200 GeV as measured by STAR

We present STAR's measurement of the $e^{+}e^{-}$ continuum as a function of centrality, invariant mass, and transverse momentum for U+U collisions at $\sqrt{s_{NN}}$ = 193 GeV. Also reported are the acceptance-corrected $e^{+}e^{-}$…

Nuclear Experiment · Physics 2016-12-19 Joey Butterworth

Study of Dimuon Production in Photon-Photon Collisions and Measurement of QED Photon Structure Functions at LEP

Muon pair production in the process e+e- -> e+e-mu+mu- is studied using the data taken at LEP1 (sqrt(s) \simeq m_Z) with the DELPHI detector during the years 1992-1995. The corresponding integrated luminosity is 138.5 pb^{-1}. The QED…

High Energy Physics - Experiment · Physics 2010-04-08 The DELPHI Collaboration , P. Abreu

Pion broadening and low-mass dilepton production

We determine mass and transverse momentum spectra of dileptons produced in Pb+Au (158 GeV/u) collisions within a pion annihilation model. A fit to the data requires simultaneous mass reduction and broadening of the in-medium rho propagator.…

High Energy Physics - Phenomenology · Physics 2016-09-06 H. -J. Schulze , D. Blaschke

Effects of a background magnetic field on dilepton radiation

We explore the feasibility of using dilepton radiations as a QGP magnetometer. We calculate the dilepton production rate in the presence of a time-dependent magnetic field typically found in heavy-ion collisions. We compute the thermal…

Nuclear Theory · Physics 2025-05-06 Han Gao , Xiang-Yu Wu , Sangyong Jeon , Charles Gale

Quantum interferences in the $\gamma N \to e^+e^- N$ reaction close to the vector meson production threshold

The exclusive photoproduction of $e^+e^-$ pairs from nucleons close to the vector meson production threshold ($1.4<\sqrt s <1.8$ GeV) results from two main processes: the emission of Bethe-Heitler pairs and the photoproduction of $\rho^0$-…

Nuclear Theory · Physics 2010-12-16 Matthias F. M. Lutz , Madeleine Soyeur

Broadening of $\rho (\to e^+e^-)$ meson produced coherently in the photonuclear reaction

The $e^+e^-$ invariant mass distribution spectra are calculated to estimate the hadron parameters of the $\rho$ meson produced coherently in the photonuclear reaction. The elementary reaction occurring in the nucleus is considered to…

Nuclear Theory · Physics 2014-04-23 Swapan Das

The reaction $\gamma p \to \pi^\circ \gamma^\prime p$ and the magnetic dipole moment of the $\Delta^+(1232)$ resonance

The reaction $\gamma p \to \pi^\circ \gamma^\prime p$ has been measured with the TAPS calorimeter at the Mainz Microtron accelerator facility MAMI for energies between $\sqrt{s}$ = 1221--1331 MeV. Cross sections differential in angle and…

Nuclear Experiment · Physics 2008-11-26 M. Kotulla , J. Ahrens , J. R. M. Annand , R. Beck , G. Caselotti , L. S. Fog , D. Hornidge , S. Janssen , B. Krusche , J. C. McGeorge , I. J. D. McGregor , K. Mengel , J. G. Messchendorp , V. Metag , R. Novotny , M. Pfeiffer , M. Rost , S. Sack , R. Sanderson , S. Schadmand , D. P. Watts

Observation of the X17 anomaly in the $^7$Li($p$,$e^+e^-$)$^8$Be direct proton-capture reaction

Angular correlation spectra of $e^+e^-$ pairs produced in the $^{7}$Li($p$,$\gamma$)$^{8}$Be nuclear reaction have been studied at the sharp $E_p$= 441 keV resonance as well as at $E_p$= 650 keV, 800 keV and 1100 keV proton beam energies.…

Nuclear Experiment · Physics 2022-05-17 N. J. Sas , A. J. Krasznahorkay , M. Csatlós , J. Gulyás , B. Kertész , A. Krasznahorkay , J. Molnár , I. Rajta , J. Timár , I. Vajda , M. N. Harakeh

Associated Production of $H^0\gamma$ or $H^0Z^0$ pairs at $\mu^+\mu^-$ Collisions

We calculate the cross-sections for the production of Standard Model Higgs Boson in association with the neutral gauge bosons (photon and Z--boson). For the case of reaction $\mu^+ \mu^- \to \gamma H^0$, complete and compact analytical…

High Energy Physics - Phenomenology · Physics 2016-09-06 V. A. Litvin , F. F. Tikhonin

Bounds on the dipole moments of the tau-neutrino via the process $e^{+}e^{-}\rightarrow \nu \bar \nu \gamma$ in a 331 model

We obtain limits on the anomalous magnetic and electric dipole moments of the $\nu_{\tau}$ through the reaction $e^{+}e^{-}\rightarrow \nu \bar \nu \gamma$ and in the framework of a 331 model. We consider initial-state radiation, and…

High Energy Physics - Phenomenology · Physics 2015-06-03 A. Gutierrez-Rodriguez

Dilepton production at SIS energies with the GiBUU transport model

We present dilepton spectra from nucleus-nucleus collisions at SIS energies, which were simulated with the GiBUU transport model in a resonance-model approach. These spectra are compared to the data published by the HADES collaboration. We…

Nuclear Theory · Physics 2013-04-08 Janus Weil , Ulrich Mosel

Dilepton Production in Nucleon-Nucleon Interactions

Starting from a realistic one--boson--exchange--model fitted to the amplitudes of elastic nucleon--nucleon scattering and the process $NN\rightarrow N\Delta$ we perform a fully relativistic and gauge invariant calculation for the dilepton…

Nuclear Theory · Physics 2009-10-28 M. Schäfer , H. C. Dönges , A. Engel , U. Mosel

Theoretical Study of the \gamma\gamma-->meson-meson Reaction

We present a unified picture which studies simultaneously the gamma gamma-->pi^+ pi^-, pi^0 pi^0, K^+ K^-, K^0 bar{K}^0, pi^0 eta reactions up to about sqrt(s)=1.4 GeV reproducing the experimental cross sections. The present work implements…

High Energy Physics - Phenomenology · Physics 2010-11-15 J. A. Oller , E. Oset

Search for Anomalous Production of Di-lepton Events with Missing Transverse Momentum in e^+e^- Collisions at sqrt{s} = 161 and 172 GeV

Events containing a pair of charged leptons and significant missing transverse momentum are selected from a data sample corresponding to a total integrated luminosity of 20.6 pb^-1 at centre-of-mass energies of 161 GeV and 172 GeV. The…

High Energy Physics - Experiment · Physics 2008-11-26 The OPAL Collaboration , K. Ackerstaff et al

(p,\pi^+-) correlations in central heavy-ion collisions at 1-2 AGeV

The proton - charged pion correlated emission is studied in the reactions Au (1.06 AGeV) + Au, Ni (1.06 and 1.93 AGeV) + Ni and Ni (1.97 AGeV) + Cu within the BUU approach. The associated invariant mass distributions are shifted to smaller…

Nuclear Theory · Physics 2011-01-25 A. B. Larionov , W. Cassing , M. Effenberger , U. Mosel

Measurement of the $\tau$ electric dipole moment using longitudinal polarization of $e^+e^-$ beams

Certain CP-odd momentum correlations in the production and subsequent decay of $\tau$ pairs in $e^+ e^-$ collisions are enhanced significantly when the $e^+$ and $e^-$ beams are longitudinally polarized. These may be used to probe the real…

High Energy Physics - Phenomenology · Physics 2009-12-30 B. Ananthanarayan , Saurabh D. Rindani