The HERA-B electron pretrigger system Baldanza, C.; Bertin, A.; Bruschi, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/1998, Letnik:
409, Številka:
1-3
Journal Article
Recenzirano
In this paper the pretrigger system designed for the electromagnetic calorimeter of the HERA-B experiment is described. This system will provide the electron candidates to the first-level trigger. ...The first results obtained with a whole readout and pretrigger prototype chain are also described.
The mid-rapidity (dσpN/dy at y=0) and total (σpN) production cross sections of Jψ mesons are measured in proton–nucleus interactions. Data collected by the HERA-B experiment in interactions of ...920 GeV/c protons with carbon, titanium and tungsten targets are used for this analysis. The Jψ mesons are reconstructed by their decay into lepton pairs. The total production cross section obtained is σpNJ/ψ=663±74±46 nb/nucleon. In addition, our result is compared with previous measurements.
A different approach to the design of CMOS MAPS has recently been proposed. By exploiting the triple well option of a CMOS commercial process, a deep n-well (DNW) MAPS sensor has been realized with a ...full in-pixel signal processing chain: charge preamplifier, shaper, discriminator and a latch. This readout approach beeing compatible with data sparsification will improve the readout speed potential of MAPS sensors. The first protoype chips, realized with STMicroelectronics 130 nm triple well process, proved the new design proposed for DNW MAPS is viable with a good sensitivity to photons from 55 Fe and electrons from 90 Sr. Extensive tests performed to characterize the second generation of the APSEL chips based on the DNW MAPS design are reported. Small 3times3 pixel matrices with full analog output have been tested with radioactive sources to characterize charge collection. Pixel noise equivalent charge (ENC) of 50 e - and signal-to-noise ratio for MIPs of about 14 have been measured. Improved pixel noise and reduced threshold dispersion (about 100 e - ) have been measured in the 8times8 matrix with a sequential readout. Based on the new DNW MAPS design a dedicated fast readout architecture to perform on-chip data sparsification is currently under development. The aim is to incorporate in the same detector the advantages of the thin CMOS sensors and similar functionalities as in hybrid pixels.
The electromagnetic calorimeter of the HERA-B experiment Avoni, G.; Baldanza, C.; Bertin, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2007, Letnik:
580, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The electromagnetic calorimeter of the
HERA-B experiment built at the HERA proton accelerator at DESY (Hamburg) is described. The construction characteristics of the detector, of the related ...front-end, readout, trigger and service electronics are discussed together with the constraints and the motivations which inspired the design philosophy. The detector performance are presented as obtained from the analysis of the data acquired during the
HERA-B running period, including calibration procedures and achievements and the electron identification capability exploiting a method, proposed here for the first time, based on the observation of the associated bremsstrahlung
γ
. Finally, some observed physical signals and a short overview of the main obtained physics results are presented.
is a fixed target experiment working on the 920 GeV proton beam of the HERA accelerator at the DESY laboratory in Hamburg. During the last data taking period (2002-2003), about 150 million dilepton ...triggers, 220 million minimum bias events and 35 million hard photon triggers were acquired. These large statistics allow detailed studies on the production of charmonium states in proton-nucleus p-A collisions, which extend for the first time into the negative Feynman-x () region. Measurements of the inclusive , \(\Upsilon\) and open charm cross sections are also ongoing. After a brief discussion of the detector and of the data samples, we report on preliminary results obtained on these physics topics.
The bb¯ production cross section in 920 GeV proton-nucleus fixed target collisions is measured by observing double muonic decays of b-flavoured hadrons in the kinematic region −0.3<xF(μ)<0.15. A ...total number of 83±12bb¯ events is obtained with a likelihood fit of the signal and background simulated events to the data. The resulting cross section is σbb¯=17.5±2.6stat±3.3sys nb/nucleon, or, when combined with a previous HERA-B measurement of similar precision, σbb¯=15.8±1.7stat±1.3sysuncorr±2.0syscorr nb/nucleon, which is consistent with recent NLO calculations.
The relation between the branching ratios and direct CP asymmetries of \(B \rightarrow K\pi\) decays and the angle \(\gamma\) of the CKM unitarity triangle is studied numerically in the general ...framework of the SU(3) approach, with minimal assumptions about the parameters not fixed by flavor-symmetry arguments. Experimental and theoretical uncertainties are subjected to a statistical treatment according to the Bayesian method. In this context, the experimental limits recently obtained by CLEO, BaBar and Belle for the direct CP asymmetries are translated into the bound \(\vert\gamma - 90^{\circ}\vert \gt 21^{\circ}\) at the 95% C.L. A detailed analysis is carried out to evaluate the conditions under which measurements of the CP averaged branching ratios may place a significant constraint on \(\gamma\). Predictions for the ratios of charged (\(R_{\mathrm{c}}\)) and neutral (\(R_{\mathrm{n}}\)) \(B \rightarrow K\pi\) decays are also presented.
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