Light Vector Mesons in the Nuclear Medium

M. H. Wood , R. Nasseripour , D. P. Weygand (1) , C. Djalali , C. Tur , U. Mosel , P. Muehlich , G. Adams , M.J. Amaryan , P. Ambrozewicz , M. Anghinolfi , G. Asryan , H. Avakian (1) , H. Bagdasaryan , N. Baillie , J.P. Ball , N.A. Baltzell , S. Barrow , M. Battaglieri , I. Bedlinskiy , M. Bektasoglu , M. Bellis , N. Benmouna , B.L. Berman , A.S. Biselli , L. Blaszczyk , S. Bouchigny (2) , S. Boiarinov (1) , R. Bradford , D. Branford , W.J. Briscoe , W.K. Brooks (1) , V.D. Burkert (1) , C. Butuceanu , J.R. Calarco , S.L. Careccia , D.S. Carman (1) , B. Carnahan , L. Casey , Si Chen , L. Cheng , P.L. Cole , P. Collins , P. Coltharp , D. Crabb , H. Crannell , V. Crede , J.P. Cummings , N. Dashyan , R. de Vita , E. de Sanctis , P.V. Degtyarenko (1) , H. Denizli , L. Dennis , A. Deur (1) , K.V. Dharmawardane , R. Dickson , G.E. Dodge , D. Doughty (1) , M. Dugger , S. Dytman , O.P. Dzyubak , H. Egiyan , K.S. Egiyan , L. El Fassi , L. Elouadrhiri (1) , P. Eugenio , G. Fedotov , G. Feldman , R.J. Feuerbach , A. Fradi (2) , H. Funsten , M. Garçon (3) , G. Gavalian , G.P. Gilfoyle , K.L. Giovanetti , F.X. Girod (3) , J.T. Goetz , C.I.O. Gordon , R.W. Gothe , M. Guidal (2) , N. Guler , L. Guo (1) , V. Gyurjyan (1) , C. Hadjidakis (2) , K. Hafidi , H. Hakobyan , R.S. Hakobyan , C. Hanretty , J. Hardie (1) , N. Hassall , F.W. Hersman , K. Hicks , I. Hleiqawi , M. Holtrop , C.E. Hyde-Wright , Y. Ilieva , D.G. Ireland , B.S. Ishkhanov , E.L. Isupov , M.M. Ito (1) , D. Jenkins , H.S. Jo (2) , J.R. Johnstone , K. Joo , H.G. Juengst , N. Kalantarians , J.D. Kellie , M. Khandaker , P. Khetarpal , W. Kim , A. Klein , F.J. Klein , A.V. Klimenko , M. Kossov , Z. Krahn , L.H. Kramer (1) , V. Kubarovsky (1) , J. Kuhn , S.E. Kuhn , S.V. Kuleshov , J. Lachniet , J.M. Laget (1, 3) , J. Langheinrich , D. Lawrence , Ji Li , K. Livingston , H.Y. Lu , M. Maccormick (2) , N. Markov , P. Mattione , S. Mcaleer , B. Mckinnon , J.W.C. Mcnabb , B.A. Mecking (1) , S. Mehrabyan , J.J. Melone , M.D. Mestayer (1) , C.A. Meyer , T. Mibe , K. Mikhailov , R. Minehart , M. Mirazita , R. Miskimen , V. Mokeev , K. Moriya , S.A. Morrow (2, 3) , M. Moteabbed , J. Mueller , E. Munevar , G.S. Mutchler , P. Nadel-Turonski , S. Niccolai (2) , G. Niculescu , I. Niculescu , B.B. Niczyporuk (1) , M.R. Niroula , R.A. Niyazov (1) , M. Nozar (1) , M. Osipenko , A.I. Ostrovidov , K. Park , E. Pasyuk , C. Paterson , S. Anefalos Pereira , J. Pierce , N. Pivnyuk , D. Pocanic , S. Pozdniakov , B.M. Preedom , J.W. Price , Y. Prok , D. Protopopescu , B.A. Raue (1) , G. Riccardi , G. Ricco , M. Ripani , B.G. Ritchie , F. Ronchetti , G. Rosner , P. Rossi , F. Sabatié (3) , J. Salamanca , C. Salgado , J.P. Santoro (1) , V. Sapunenko (1) , R.A. Schumacher , V.S. Serov , Y.G. Sharabian (1) , D. Sharov , N.V. Shvedunov , E.S. Smith , L.C. Smith (1) , D.I. Sober , D. Sokhan , A. Stavinsky , S. Stepanyan (1) , S.S. Stepanyan , B.E. Stokes , P. Stoler , I.I. Strakovsky , S. Strauch , M. Taiuti , D.J. Tedeschi , A. Tkabladze , S. Tkachenko , L. Todor , M. Ungaro , M.F. Vineyard (1) , A.V. Vlassov , D.P. Watts , L.B. Weinstein , M. Williams , E. Wolin (1) , A. Yegneswaran (1) , L. Zana , B. Zhang , J. Zhang , B. Zhao , Z.W. Zhao

1 Jefferson Lab - Thomas Jefferson National Accelerator Facility
2 IPNO - Institut de Physique Nucléaire d'Orsay
3 DPHN - Département de Physique Nucléaire (ex SPhN)

The light vector mesons ($\rho$, $\omega$, and $\phi$) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the $\rho$ meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to $e^{+}e^{-}$. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The $\rho$ meson mass spectrum was extracted after the $\omega$ and $\phi$ signals were removed in a nearly model-independent way. Comparisons were made between the $\rho$ mass spectra from the heavy targets ($A > 2$) with the mass spectrum extracted from the deuterium target. With respect to the $\rho$-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body effects such as collisional broadening and Fermi motion.

Mots clés: light vector mesons; in-medium modifications; chiral symmetry

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

M. H. Wood, R. Nasseripour, D. P. Weygand, C. Djalali, C. Tur, et al.. Light Vector Mesons in the Nuclear Medium. Physical Review C, 2008, 78, pp.015201. ⟨10.1103/PhysRevC.78.015201⟩. ⟨in2p3-00264862⟩