TY - JOUR
TI - Excess of continuum dimuon production at masses between threshold and
the J/Psi in S-W interactions at 200 GeV/c/nucleon
AU - Angelis, ALS
AU - Antos, J
AU - Beaulieu, M
AU - Beker, H
AU - Bystricky, J
AU - and Catanesi, MG
AU - Cerello, P
AU - Dagan, S
AU - Dellacasa, G
AU - Di
AU - Liberto, S
AU - Dolgoshein, B
AU - Esten, M
AU - Fabjan, CW
AU - Gaidot, A
AU - and Gallio, M
AU - Giubellino, P
AU - Goerlach, U
AU - Guerra, C
AU - Hamel,
AU - LA
AU - Konovalov, S
AU - Kralik, I
AU - London, G
AU - Martelli, F and
AU - Martin, JP
AU - Masera, M
AU - Mazzoni, MA
AU - Meddi, F
AU - Muciaccia, MT
AU - and Muraviev, S
AU - Nomerotsky, A
AU - Oren, Y
AU - Pansart, JP and
AU - Poulard, G
AU - Ramello, L
AU - Riccati, L
AU - Rosa, G
AU - Sandor, L and
AU - Sarris, M
AU - Scomparin, E
AU - Shmeleva, A
AU - Simone, S
AU - Smirnov, S
AU - and Taras, P
AU - Urban, J
AU - Vercellin, E
AU - HELIOS 3 Collaboration
JO - The European Physical Journal C - Particles and Fields
PY - 2000
VL - 13
TODO - 3
SP - 433-452
PB - Springer-Verlag
SN - 1434-6044, 1434-6052
TODO - 10.1007/s100520000314
TODO - null
TODO - Results are presented on dimuon production for invariant masses ranging
from the dimuon threshold up to the J/Psi meson. Proton-tungsten and
sulphur-tungsten interactions at 200 GeV/c/nucleon were measured over a
large kinematic region, using the HELIOS/3 dimuon spectrometer at the
CERN SPS. In the continuum regions between the dimuon threshold and the
rho/omega mesons, and between the phi and J/Psi mesons, an excess is
observed in S-W interactions relative to minimum bias p-W interactions.
The observed excess is continuous over the explored mass range and has
no apparent resonant structure. In the low mass region the dimuon yield
increases by (76 +/- 4)% of the corresponding p-W dimuon spectrum,
whereas in the higher mass region the excess amounts to 2.4 +/- 0.3
times the p-W yield. The observed excess for the low mass region follows
an exponential transverse mass distribution with an average inverse
slope parameter T of (190 +/- 5) MeV/c(2), constant for all but the
lowest charged multiplicity interval and consistent with the slope of
the excess in the higher mass region. In the invariant mass range of
1.35-2.5 GeV/c(2) the continuum dimuon mass distribution observed in p-W
interactions can be quantitatively understood as a sum of three expected
contributions (vector meson decays, semileptonic charm decays and
Drell-Yan process), but both in central and in minimum bias S-W
interactions an excess is observed with respect to these sources which
does not depend on centrality, nor very strongly on the transverse
momentum.
ER -