We present the first measurement of the angular distribution for the exclusive process (p) over barp -> psi(2S) -> e(+)e(-) based on a sample of 6844 events collected by the Fermilab E835 experiment. We find that the angular distribution is well described by the expected functional form d N/d cos theta* proportional to 1 + lambda cos(2) theta*, where theta* is the angle between the antiproton and the electron in the center of mass frame, with lambda = 0.67 +/- 0.15(stat) +/- 0.04(sys). The measured value for lambda implies a small but non-zero psi(2S) helicity 0 formation amplitude in (p) over barp, comparable to what is observed in J/psi decays to baryon pairs.

Measurement of the angular distribution in (p)over-barp ->psi(2S)-> e(+)e(-)

ANDREOTTI, Mirco;CALABRESE, Roberto;CIBINETTO, Gianluigi;DALPIAZ, Pietro;LUPPI, Eleonora;NEGRINI, Matteo;STANCARI, Michelle Dawn;
2005

Abstract

We present the first measurement of the angular distribution for the exclusive process (p) over barp -> psi(2S) -> e(+)e(-) based on a sample of 6844 events collected by the Fermilab E835 experiment. We find that the angular distribution is well described by the expected functional form d N/d cos theta* proportional to 1 + lambda cos(2) theta*, where theta* is the angle between the antiproton and the electron in the center of mass frame, with lambda = 0.67 +/- 0.15(stat) +/- 0.04(sys). The measured value for lambda implies a small but non-zero psi(2S) helicity 0 formation amplitude in (p) over barp, comparable to what is observed in J/psi decays to baryon pairs.
2005
Ambrogiani, M; Andreotti, Mirco; Argiro, S; Bagnasco, S; Baldini, W; Bettoni, D; Borreani, G; Buzzo, A; Calabrese, Roberto; Cester, R; Cibinetto, Gianluigi; Dalpiaz, Pietro; Fan, X; Garzoglio, G; Gollwitzer, Ke; Graham, M; Hahn, A; Hu, M; Jin, S; Joffe, D; Kasper, J; Lasio, G; LO VETERE, M; Luppi, Eleonora; Maas, P; Macri, M; Mandelkern, M; Marchetto, E; Marinelli, M; Marsh, W; Martini, M; Menichetti, E; Metreveli, Z; Mussa, R; Negrini, Matteo; Obertino, Mm; Pallavicini, M; Pastrone, N; Patrignani, C; Pedlar, Tk; Pordes, S; Robutti, E; Roethel, W; Rosen, J; Rumerio, P; Rusack, R; Santroni, A; Schultz, J; Seo, Sh; Seth, Kk; Stancari, G; Stancari, Michelle Dawn; Streets, J; Tomaradze, A; Uman, I; Vidnovic, T; Werkema, S; Zioulas, G; Zweber, P.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/1211478
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