Modern experiments search for extremely rare processes hidden in much larger background levels. As the experiment complexity, the accelerator backgrounds and luminosity increase we need increasingly ...exclusive selections to efficiently select the rare events inside the huge background. We present a fast, high-quality, track-based event selection for the self-triggered SLIM5 silicon telescope. This is an R&D experiment whose innovative trigger will show that high rejection factors and manageable trigger rates can be achieved using fine-granularity, low-material tracking detectors.
The SLIM5 low mass silicon tracker demonstrator Bettarini, S.; Ratti, L.; Rizzo, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2010, Letnik:
623, Številka:
3
Journal Article
Recenzirano
A low material budget silicon demonstrator has been tested by the SLIM5 collaboration with 12
GeV/
c protons at the PS-T9 beam line at CERN. Two devices were placed inside a reference telescope and ...their characteristics were measured. The first was a 4k-Pixel Matrix of Deep N Well MAPS, developed in a 130
nm CMOS technology, providing digital sparsified readout. The other one was a high resistivity double-sided silicon detector, with short strips at a
45
∘
angle to the detector's edge, read out by the FSSR2 chip. In this paper we describe the main features of both sensors. The primary goal of the test was to measure the efficiency and the resolution of the DUTs under different conditions of threshold setting and incident angle of the impinging particles. The data-driven approach of the readout chips has been fully exploited by the DAQ system to take data with a track-based level-1 trigger provided by a pattern matching algorithm with very low latency.
The increase of the luminosity in the High Luminosity upgrade of the CERN Large Hadron Collider (HL-LHC) will require the use of Tracker information in the evaluation of the Level-1 trigger in order ...to keep the trigger rate acceptable (i.e.: <; 1MHz). A custom real-time system will be needed to extract the track information within the latency constraints (<;10usec). We developed the prototype of the building block of this system, the Pattern Recognition Mezzanine (PRM) that combines the power of both Associative Memory custom ASICs and modern FPGA devices. The architecture and the functionalities of the PRM are described here.
A search for a narrow Higgs boson resonance in the diphoton mass spectrum is presented based on data corresponding to 7.0 fb^-1 of integrated luminosity from p-pbar collisions at sqrt(s) = 1.96 TeV ...collected by the CDF experiment. No evidence of such a resonance is observed, and upper limits are set on the cross section times branching ratio of the resonant state as a function of Higgs boson mass. The limits are interpreted in the context of the standard model and one fermiophobic benchmark model where the data exclude fermiophobic Higgs bosons with masses below 114 GeV/c^2 at a 95% Bayesian credibility level.
We report the first observation of the baryonic flavor-changing neutral current decay Λb0→Λμ+μ- with 24 signal events and a statistical significance of 5.8 Gaussian standard deviations. This ...measurement uses a pp¯ collisions data sample corresponding to 6.8fb-1 at s=1.96TeV collected by the CDF II detector at the Tevatron collider. The total and differential branching ratios for Λb0→Λμ+μ- are measured. We find B(Λb0→Λμ+μ-)=1.73±0.42(stat)±(syst)×10-6. We also report the first measurement of the differential branching ratio of Bs0→ϕμ+μ-, using 49 signal events. In addition, we report branching ratios for B+→K+μ+μ-, B0→K0μ+μ-, and B→K*(892)μ+μ- decays.
A search has been performed for Bs0→μ+μ- and B0→μ+μ- decays using 7fb-1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. The observed number of B0 ...candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of B(B0→μ+μ-)<6.0×10-9 at 95% confidence level. We observe an excess of Bs0 candidates. The probability that the background processes alone could produce such an excess or larger is 0.27%. The probability that the combination of background and the expected standard model rate of Bs0→μ+μ- could produce such an excess or larger is 1.9%. These data are used to determine B(Bs0→μ+μ-)=(1.8-0.9+1.1)×10-8 and provide an upper limit of B(Bs0→μ+μ-)<4.0×10-8 at 95% confidence level.
The results obtained by the Slim5 collaboration on a low material budget tracking silicon demonstrator put on a 12
GeV/
c
proton test beam at CERN are reported. Inside a reference telescope, two ...different and innovative detectors were placed for careful tests. The first was a 4k-Pixel Matrix of Deep N Well MAPS, developed in a 130
nm CMOS Technology, square pixels
50
μ
m
wide, thinned down to
100
μ
m
and equipped with a digital sparsified readout running up to 50
MHz. The other was a high resistivity double sided silicon detector,
200
μ
m
thick, with short strips with
50
μ
m
pitch at
45
∘
angle to the detector's edge. The detectors were equipped with dedicated fast readout architectures performing on-chip data sparsification and providing the timing information for the hits. The criteria followed in the design of the pixel sensor and of the pixel readout architecture will be reviewed. Preliminary measurements of the pixel charge collection, track detection efficiencies and resolutions of pixel and strip sensors are discussed.
The data driven architecture of the readout chips has been fully exploited in the test beam by a data acquisition system able to collect on electronic board up to 2.5 Million events per second before triggering. By using a dedicated Associative Memory board, we were able to perform a level 1 trigger system, with minimal latency, identifying cleanly tracks traversing the detectors. System architecture and main performances are shown.
Deep n-well MAPS in a 130 nm CMOS technology: Beam test results Lusiani, A; Manghisoni, M; Re, V ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2010, Letnik:
623, Številka:
1
Journal Article
Recenzirano
We report on recent beam test results for the APSEL4D chip, a new deep n-well MAPS prototype with a full in-pixel signal processing chain obtained by exploiting the triple well option of the CMOS ...inline image process. The APSEL4D chip consists of a 4096 pixel matrix (32 rows and 128 columns) with inline image pixel cell area, with custom readout architecture capable of performing data sparsification at pixel level. APSEL4D has been characterized in terms of charge collection efficiency and intrinsic spatial resolution under different conditions of discriminator threshold settings using a 12 GeV/c proton beam in the T9 area of the CERN PS. We observe a maximum hit efficiency of 92% and we estimate an intrinsic resolution of about inline image. The data driven approach of the tracking detector readout chips has been successfully used to demonstrate the possibility to build a Level 1 trigger system based on associative memories. The analysis of the beam test data is critically reviewed along with the characterization of the device under test.
We report a study of the invariant mass distribution of jet pairs produced in association with a W boson using data collected with the CDF detector which correspond to an integrated luminosity of 4.3 ...fb^-1. The observed distribution has an excess in the 120-160 GeV/c^2 mass range which is not described by current theoretical predictions within the statistical and systematic uncertainties. In this letter we report studies of the properties of this excess.
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