Nucl.Instrum.Meth.A582:575-580,2007 The electromagnetic calorimeter of PANDA at the FAIR facility will rely on an
operation of lead tungstate (PWO) scintillation crystals at temperatures near
-25 ...deg.C to provide sufficient resolution for photons in the energy range from
8 GeV down to 10 MeV. Radiation hardness of PWO crystals was studied at the
IHEP (Protvino) irradiation facility in the temperature range from room
temperature down to -25 deg.C. These studies have indicated a significantly
different behaviour in the time evolution of the damaging processes well below
room temperature. Different signal loss levels at the same dose rate, but at
different temperatures were observed. The effect of a deep suppression of the
crystal recovery process at temperatures below
0 deg.C has been seen.
Phys.Rev.C80:024905,2009 We present a systematic analysis of two-pion interferometry in Au+Au
collisions at $\sqrt{s_{\rm{NN}}}$ = 62.4 GeV and Cu+Cu collisions at
$\sqrt{s_{\rm{NN}}}$ = 62.4 and 200 ...GeV using the STAR detector at RHIC. The
multiplicity and transverse momentum dependences of the extracted correlation
lengths (radii) are studied. The scaling with charged particle multiplicity of
the apparent system volume at final interaction is studied for the RHIC energy
domain. The multiplicity scaling of the measured correlation radii is found to
be independent of colliding system and collision energy.
We present recent results of single-spin asymmetry $A_N$ measurements in
$\pi^0$ inclusive production. Asymmetry was measured in $\pi^-p$ and $pp$
interactions at 40 and 70 GeV correspondingly. ...Significant asymmetry was
observed in the polarized target fragmentation region. The results are in
agreement with "universal threshold" of single-spin asymmetry.
We report the measurement of charged D* mesons in inclusive jets produced in proton-proton collisions at a center-of-mass energy sqrt(s)=200 GeV with the STAR experiment at the Relativistic Heavy Ion ...Collider. For D* mesons with fractional momenta 0.2
Phys.Atom.Nucl.70:1058-1073,2007 A precise measurement of the angle $\alpha$ in the CKM triangle is very
important for a complete test of Standard Model. A theoretically clean method
to extract ...$\alpha$ is provided by B$^0 \to \rho \pi$ decays. Monte Carlo
simulations to obtain the BTeV reconstruction efficiency and to estimate the
signal to background ratio for these decays were performed. Finally the
time-dependent Dalitz plot analysis, using the isospin amplitude formalism for
tree and penguin contributions, was carried out. It was shown that in one year
of data taking BTeV could achieve an accuracy on $\alpha$ better than
5$^{\circ}$.
Nucl.Instrum.Meth.A550:543-550,2005 Radiation damage in lead tungstate crystals reduces their transparency. The
calibration that relates the amount of light detected in such crystals to
incident ...energy of photons or electrons is of paramount importance to
maintaining the energy resolution the detection system. We report on tests of
lead tungstate crystals, read out by photomultiplier tubes, exposed to
irradiation by monoenergetic electron or pion beams. The beam electrons
themselves were used to measure the scintillation light output, and a blue
light emitting diode (LED) was used to track variations of crystals
transparency. We report on the correlation of the LED measurement with
radiation damage by the beams and also show that it can accurately monitor the
crystals recovery from such damage.
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