Baryon resonance production and dielectron decays in proton-proton collisions at 3.5 GeV
Tóm tắt
We report on baryon resonance production and decay in proton-proton collisions at a kinetic energy of 3.5 GeV based on data measured with HADES. The exclusive channels
$ pp \rightarrow np\pi^{+}$
and
$ pp\rightarrow pp\pi^{0}$
as well as
$ pp\rightarrow ppe^{+}e^{-}$
are studied simultaneously for the first time. The invariant masses and angular distributions of the pion-nucleon systems were studied and compared to simulations based on a resonance model ansatz assuming saturation of the pion production by an incoherent sum of baryonic resonances (R with masses < 2 GeV/c2. A very good description of the one-pion production is achieved allowing for an estimate of individual baryon resonance production cross sections which are used as input to calculate the dielectron yields from
$ R\rightarrow pe^{+}e^{-}$
decays. Two models of the resonance decays into dielectrons are examined assuming a point-like
$ RN\gamma^{*}$
coupling and the dominance of the
$ \rho$
meson. The results of model calculations are compared to data from the exclusive
$ ppe^{+}e^{-}$
channel by means of the dielectron and
$ pe^{+}e^{-}$
invariant mass distributions.
Tài liệu tham khảo
I.G. Aznauryan, V.D. Burkert, Prog. Part. Nucl. Phys. 67, 1 (2012)
J.J. Sakurai, Ann. Phys. 1, 1 (1960)
N.M. Kroll, T.D. Lee, B. Zumino, Phys. Rev. 157, 1376 (1960)
A. Faessler, C. Fuchs, M.I. Krivoruchenko, B.V. Martemyanov, J. Phys. G: Nucl. Part. Phys. 29, 603 (2003)
M.I. Krivoruchenko, B.V. Martemyanov, Ann. Phys. 296, 299 (2002)
G. Ramalho, M.T. Peña, Phys. Rev. D 85, 113014 (2012)
CERES Collaboration (D. Adamova et al.), Phys. Lett. B 666, 425 (2008)
NA60 Collaboration (R. Arnaldi et al.), Phys. Rev. Lett. 96, 162302 (2006)
STAR Collaboration (X. Dong), Nucl. Phys. A 904, 19c (2013)
PHENIX Collaboration (A. Adare et al.), Phys. Rev. C 81, 034911 (2010)
H. van Hees, R. Rapp, Nucl. Phys. A 806, 339 (2008)
W. Peters et al., Nucl. Phys. A 632, 109 (1998)
S. Leupold, V. Metag, U. Mosel, Int. J. Mod. Phys. E 19, 147 (2010)
R. Rapp, J. Wambach, Adv. Nucl. Phys. A 25, 1 (2000)
HADES Collaboration (G. Agakishiev et al.), Eur. Phys. J. A 48, 64 (2012)
HADES Collaboration (G. Agakishiev et al.), Phys. Lett. B 715, 304 (2012)
J. Weil, H. van Hees, U. Mosel, Eur. Phys. J. A 48, 111 (2012) J. Weil, private communication
Q. Wan, F. Iachello, Int. J. Mod. Phys. A 20, 1846 (2005)
O. Buss, T. Gaitanos, K. Gallmeister, H. van Hees, M. Kaskulov, O. Lalakulich, A.B. Larionov, T. Leitner, J. Weil, U. Mosel, Phys. Rep. 512, 1 (2012)
S. Teis, W. Cassing, M. Effenberger, A. Hombach, U. Mosel, Gy. Wolf, Z. Phys. A 356, 421 (1997)
V. Dmitriev, O. Sushkov, C. Gaarde, Nucl. Phys. A 459, 53 (1986)
HADES Collaboration (G. Agakichiev et al.), Eur. Phys. J. A 48, 74 (2012)
S.A. Bass, M. Belkacem, M. Bleicher, M. Brandstetter, L. Bravina, C. Ernst, L. Gerland, M. Hofmann, S. Hofmann, J. Konopka, G. Mao, L. Neise, S. Soff, C. Spieles, H. Weber, L.A. Winckelmann, H. Stöcker, W. Greiner, Ch. Hartnack, J. Aichelin, N. Amelin, Prog. Part. Nucl. Phys. 41, 255 (1998)
J. Weil, K. Gallmeister, U. Mosel, PoS BORMIO2011, 053 (2011) arXiv:1105.0314
E.L. Bratkovskaya, W. Cassing, Nucl. Phys. A 807, 214 (2008)
M. Zetenyi, Gy. Wolf, Heavy Ion Phys. 17, 27 (2003)
HADES Collaboration (G. Agakichiev et al.), Eur. Phys. J. A 41, 243 (2009)
I. Fröhlich et al., PoS ACAT2007, 076 (2007) arXiv: 0708.2382v2
Particle Data Group (J. Beringer et al.), Phys. Rev. D 86, 010001 (2012)
C. Ernst, S.A. Bass, M. Belkacem, H. Stöcker, W. Greiner, Phys. Rev. C 58, 447 (1998)
Gy. Wolf, G. Batko, W. Cassing, U. Mosel, K. Niita, M. Schäfer, Nucl. Phys. A 517, 615 (1990)
M.I. Krivoruchenko, A. Faessler, Phys. Rev. D 65, 017502 (2002)
E. Colton, P.E. Schlein, E. Gellert, G.A. Smith, Phys. Rev. D 3, 1063 (1971)
V.P. Andreev et al., Phys. Rev. C 50, 15 (1994)
COSY-TOF Collaboration (M. Abdel-Bary et al.), Eur. Phys. J. A 44, 7 (2010)
K. Teilab, The production of eta and omega mesons in 3.5 GeV $p+p$ interaction in HADES, PhD Thesis, University of Frankfurt (2012)
DISTO Collaboration (F. Balestra et al.), Phys. Rev. Lett. 89, 092001 (2002)
E.L. Bratkovskaya, J. Aichelin, M. Thomere, S. Vogel, M. Bleicher, Phys. Rev. C 87, 064907 (2013)
J. Koch, N. Ohtsuka, E. Moniz, Ann. Phys. 154, 99 (1984)
K. Schmidt, E. Santini, S. Vogel, C. Sturm, M. Bleicher, H. Stöcker, Phys. Rev. C 79, 064908 (2009)
DLS Collaboration (W.K. Wilson et al.), Phys. Rev. C 57, 1865 (1998)
M. Shrestha, D.M. Manley, Phys. Rev. C 86, 055203 (2012)
A.V. Anisovich, R. Beck, E. Klempt, V.A. Nikonov, A.V. Sarantsev, U. Thoma, Eur. Phys. J. A 48, 15 (2012)
CLAS Collaboration (V. Mokeev et al.), Phys. Rev. C 86, 035203 (2012)
HADES Collaboration (G. Agakichiev et al.), Phys. Rev. C 85, 035203 (2012)