We have searched for the K{sup +} {yields} {pi}{sup +}{gamma}{gamma} decay in the kinematic region with {pi}{sup +} momentum close to the end point. No events were observed, and the 90% ...confidence-level upper limit on the partial branching ratio was obtained, B(K{sup +} {yields} {pi}{sup +}{gamma}{gamma}, P > 213 MeV/c) < 8.3 x 10{sup -9} under the assumption of chiral perturbation theory including next-to-leading order ''unitarity'' corrections. The same data were used to determine an upper limit on the K{sup +} {yields} {pi}{sup +}{gamma} branching ratio of 2.3 x 10{sup -9} at the 90% confidence level.
Upgrade of the level-0 trigger system for BNL-E949 Yoshioka, T.; Nomachi, M.; Artamanov, A. ...
IEEE transactions on nuclear science,
2004-June, 2004-06-00, 20040601, Letnik:
51, Številka:
3
Journal Article
Recenzirano
A new programmable trigger board and digital mean-timer modules using complex programmable logic device have been introduced to the trigger system of the BNL-E949 experiment. The online dead time was ...reduced from 4.0% to 1.7% by introducing an on-chip prescaler to the programmable trigger board. The acceptance loss of the online photon veto was reduced from 4.9% to 1.8% by introducing the mean-timer modules.
The ALEPH silicon vertex detector is the first detector operating in a colliding beam environment that uses silicon strip detectors which provide readout on both sides and hence a three-dimensional ...point measurement for the trajectory of charged particles. The detector system was commissioned successfully at the e
+e
− collider LEP at the research centre CERN, Switzerland, during the year 1991 while taking data at the Z
0 resonance. The achieved spatial resolution of the complete 73 728 channel device (intrinsic plus alignment) is 12 μm in the
r-
f view and 12 μm in the
z view. The design and construction of the entire detector system are discussed in detail and the experience gained in running the detector will be described with special emphasis on the uses of this novel tracking device for the physics of short-lived heavy particles produced in the decays of the Z
0 resonance.
Central tracking chamber with inflated cathode-strip foils Blackmore, E.W.; Bryman, D.A.; Kuno, Y. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
1998, Letnik:
404, Številka:
2
Journal Article
Recenzirano
A new cylindrical low-mass central drift chamber has been constructed for the
K
+ → π
+ν
ν
experiment at BNL (E787). The chamber consists of twelve layers of axial wire cells and six layers of thin ...cathode-strip foils, four of which are supported by differential gas pressure. The momentum resolution (RMS) for muons and pions in the range 150–250 MeV/
c is found to be about 0.9%.
The differential cross section for the process $Z/\gamma^*\rightarrow ll$ ($l=e,\mu$) as a function of dilepton invariant mass is measured in pp collisions at $\sqrt{s}=$7 TeV at the LHC using the ...ATLAS detector. The measurement is performed in the $e$ and $\mu$ channels for invariant masses between 26 GeV and 66 GeV using an integrated luminosity of 1.6 fb$^{-1}$ collected in 2011 and these measurements are combined. The analysis is extended to invariant masses as low as 12 GeV in the muon channel using 35 pb$^{-1}$ of data collected in 2010. The cross sections are determined within fiducial acceptance regions and corrections to extrapolate the measurements to the full kinematic range are provided. Next-to-next-to-leading-order QCD predictions provide a significantly better description of the results than next-to-leading-order QCD calculations, unless the latter are matched to a parton shower calculation.
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