Phys.Rev.Lett. 89 (2002) 092001 Total and differential cross sections for the exclusive reaction pp->pp rho^0
observed via the pi+pi- decay channel have been measured at beam momentum=3.67
GeV/c. The ...observed total meson production cross section is determined to be
23.4 +- 0.8 +-8 microb and is significantly lower than typical cross sections
used in model calculations for heavy ion collisions. The differential cross
sections measured indicate a strong anisotropy cos^2(theta^{CM}) in the rho^0
meson production.
A High Acceptance DiElectron Spectrometer (HADES) has been proposed at the SIS accelerator of GSI in order to measure
e
+e
−
pairs produced in proton, meson and heavy ion induced collisions. HADES ...will be able to operate at the highest luminosities available at SIS in an environment of high hadron and photon background. A Ring Imaging Čerenkov Counter (RICH) serves for electron identification. Momentum measurement is achieved with a magnetic spectrometer consisting of superconducting toroidal coils and mini drift chambers for tracking. Arrays of pre-shower detectors and TOF wall are positioned behind the drift chambers for electron trigger purposes and for measuring the charged particle multiplicity. The detector features have been investigated in detailed simulations. The expected performance of the system in terms of efficiency, resolution and residual background are presented.
Nucl.Instrum.Meth. A380 (1996) 586-596 Design studies for a second generation Dilepton Spectrometer to be built at
the SIS accelerator of GSI are presented. The basic design parameters of this
system ...are specified and the different detector components for charged particle
tracking and for lepton identification are described. The geometrical
acceptance for lepton pairs is given. Results on single track momentum
resolution and on lepton pair mass resolution are reported.
Phys.Rev.C63:024004,2001 The exclusive production cross sections for $\omega$ and $\phi$ mesons have
been measured in proton-proton reactions at $p_{lab}=3.67$ GeV/c. The observed
$\phi/\omega$ cross ...section ratio is $(3.8\pm0.2^{+1.2}_{-0.9})\times 10^{-3}$.
After phase space corrections, this ratio is enhanced by about an order of
magnitude relative to naive predictions based upon the Okubo-Zweig-Iizuka (OZI)
rule, in comparison to an enhancement by a factor $\sim 3$ previously observed
at higher beam momenta. The modest increase of this enhancement near the
production threshold is compared to the much larger increase of the
$\phi/\omega$ ratio observed in specific channels of $\bar pp$ annihilation
experiments. Furthermore, differential cross section results are also presented
which indicate that although the $\phi$ meson is predominantly produced from a
$^3P_1$ proton-proton entrance channel, other partial waves contribute
significantly to the production mechanism at this beam momentum.
Phys.Lett. B491 (2000) 29-35 The ratio of the total exclusive production cross sections for $\eta\prime$
and $\eta$ mesons has been measured in the $pp$ reaction at $p_{beam}=3.67$
GeV/c. The ...observed $\eta\prime/\eta$ ratio is
$(0.83\pm{0.11}^{+0.23}_{-0.18})\times 10^{-2}$ from which the exclusive
$\eta\prime$ meson production cross section is determined to be
$(1.12\pm{0.15}^{+0.42}_{-0.31})\mu b$. Differential cross section
distributions have been measured. Their shape is consistent with isotropic
$\eta\prime$ meson production.
Phys.Lett. B468 (1999) 7-12 The total cross section of the reaction $pp\to ppK^+K^-$ has been determined
for proton--proton reactions with $p_{beam}=3.67 GeV/c$. This represents the
first cross ...section measurement of the $pp \to ppK^-K^+$ channel near
threshold, and is equivalent to the inclusive $pp\to ppK^-X$ cross section at
this beam momentum. The cross section determined at this beam momentum is about
a factor 20 lower than that for inclusive $pp\to ppK^+X$ meson production at
the same CM energy above the corresponding threshold. This large difference in
the $K^+$ and $K^-$ meson inclusive production cross sections in proton-proton
reactions is in strong contrast to cross sections measured in sub-threshold
heavy ion collisions, which are similar in magnitude at the same energy per
nucleon below the respective thresholds.
Total and differential cross sections for the exclusive reaction pp->pp rho^0 observed via the pi+pi- decay channel have been measured at beam momentum=3.67 GeV/c. The observed total meson production ...cross section is determined to be 23.4 +- 0.8 +-8 microb and is significantly lower than typical cross sections used in model calculations for heavy ion collisions. The differential cross sections measured indicate a strong anisotropy cos^2(theta^{CM}) in the rho^0 meson production.
Phys.Rev.Lett. 83 (1999) 1534-1537 We report the first polarization transfer measurements for exclusive hyperon
production reactions. The normal spin transfer coefficient DNN for pp -> p K+
Lambda is ...large and negative for forward Lambda production at a beam momentum
of 3.67 GeV/c, a result qualitatively consistent with expectations for a
mechanism dominated by kaon-exchange and rescattering. The sign of DNN is
opposite to that observed in the fragmentation regime for inclusive Lambda
production at much higher energies.
Design studies for a second generation Dilepton Spectrometer to be built at the SIS accelerator of GSI are presented. The basic design parameters of this system are specified and the different ...detector components for charged particle tracking and for lepton identification are described. The geometrical acceptance for lepton pairs is given. Results on single track momentum resolution and on lepton pair mass resolution are reported.
The exclusive production cross sections for \(\omega\) and \(\phi\) mesons have been measured in proton-proton reactions at \(p_{lab}=3.67\) GeV/c. The observed \(\phi/\omega\) cross section ratio is ...\((3.8\pm0.2^{+1.2}_{-0.9})\times 10^{-3}\). After phase space corrections, this ratio is enhanced by about an order of magnitude relative to naive predictions based upon the Okubo-Zweig-Iizuka (OZI) rule, in comparison to an enhancement by a factor \(\sim 3\) previously observed at higher beam momenta. The modest increase of this enhancement near the production threshold is compared to the much larger increase of the \(\phi/\omega\) ratio observed in specific channels of \(\bar pp\) annihilation experiments. Furthermore, differential cross section results are also presented which indicate that although the \(\phi\) meson is predominantly produced from a \(^3P_1\) proton-proton entrance channel, other partial waves contribute significantly to the production mechanism at this beam momentum.
