PACIFIC: SiPM readout ASIC for LHCb upgrade de Cos, José Mazorra; Chanal, Hervé; Comerma Montells, Albert ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2018, Letnik:
912
Journal Article
Recenzirano
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A new 64-channel mixed-signal ASIC is presented: PACIFIC. It was developed in TSMC 130 nm CMOS technology for the readout of the Scintillating Fibre Tracker, as a part of the LHCb upgrade. This ...detector is based on 250 μ m scintillating fibers readout by custom designed 128-channel silicon photomultiplier arrays. It will cover a total area of 340 m2, distributed over the 12 planes that compose it. The sensors are connected directly to PACIFIC without any interface components. The ASIC acquires the current pulses using a current conveyor. A fast double pole-zero cancellation shaper is used to minimize spillover. The charge is then collected using gated integrators, with a twofold interleaved scheme to minimize dead time. The resulting voltage level is digitized with a configurable 2 bit non-linear flash ADC. The output is a 320 Mbps differential signal produced by the serializers, which gather the results from four adjacent channels.
•A new mix-signal silicon photomultiplier readout ASIC is presented.•Direct anode connection with voltage and impedance control at this node.•Fast shaping and integration with configurable 2-bit non-linear output.•It has demonstrated single photoelectron detection capability.
Measurements of the cross section for producing b quarks in the reaction pp -> b (b) over barX are reported in 7 and 13 TeV collisions at the LHC as a function of the pseudorapidity. in the range 2 < ...eta < 5 covered by the acceptance of the LHCb experiment. The measurements are done using semileptonic decays of b-flavored hadrons decaying into a ground-state charmed hadron in association with a muon. The cross sections in the covered. range are 72.0 +/- 0.3 +/- 6.8 and 154.3 +/- 1.5 +/- 14.3 +/- mu b for 7 and 13 TeV. The ratio is 2.14 +/- 0.02 +/- 0.13, where the quoted uncertainties are statistical and systematic, respectively. The agreement with theoretical expectation is good at 7 TeV, but differs somewhat at 13 TeV. The measured ratio of cross sections is larger at lower eta than the model prediction.
The cross section for prompt antiproton production in collisions of protons with an energy of 6.5 TeV incident on helium nuclei at rest is measured with the LHCb experiment from a data set ...corresponding to an integrated luminosity of 0.5 nb − 1 . The target is provided by injecting helium gas into the LHC beam line at the LHCb interaction point. The reported results, covering antiproton momenta between 12 and 110 GeV / c , represent the first direct determination of the antiproton production cross section in p − He collisions, and impact the interpretation of recent results on antiproton cosmic rays from space-borne experiments.
The cross section for prompt antiproton production in collisions of protons with an energy of 6.5 TeV incident on helium nuclei at rest is measured with the LHCb experiment from a data set ...corresponding to an integrated luminosity of 0.5 nb − 1 . The target is provided by injecting helium gas into the LHC beam line at the LHCb interaction point. The reported results, covering antiproton momenta between 12 and 110 GeV / c , represent the first direct determination of the antiproton production cross section in p − He collisions, and impact the interpretation of recent results on antiproton cosmic rays from space-borne experiments.
The doubly charmed baryon decay Ξ + + c c → Ξ + c π + is observed for the first time, with a statistical significance of 5.9 σ , confirming a recent observation of the baryon in the Λ + c K − π + π + ...final state. The data sample used corresponds to an integrated luminosity of 1.7 fb − 1 , collected by the LHCb experiment in p p collisions at a center-of-mass energy of 13 TeV. The Ξ + + c c mass is measured to be 3620.6 ± 1.5 ( stat ) ± 0.4 ( syst ) ± 0.3 ( Ξ + c ) MeV / c 2 and is consistent with the previous result. The ratio of branching fractions between the decay modes is measured to be B ( Ξ + + c c → Ξ + c π + ) × B ( Ξ + c → p K − π + ) / B ( Ξ + + c c → Λ + c K − π + π + ) × B ( Λ + c → p K − π + ) = 0.035 ± 0.009 ( stat ) ± 0.003 ( syst )
The doubly charmed baryon decay Ξ + + c c → Ξ + c π + is observed for the first time, with a statistical significance of 5.9 σ , confirming a recent observation of the baryon in the Λ + c K − π + π + ...final state. The data sample used corresponds to an integrated luminosity of 1.7 fb − 1 , collected by the LHCb experiment in p p collisions at a center-of-mass energy of 13 TeV. The Ξ + + c c mass is measured to be 3620.6 ± 1.5 ( stat ) ± 0.4 ( syst ) ± 0.3 ( Ξ + c ) MeV / c 2 and is consistent with the previous result. The ratio of branching fractions between the decay modes is measured to be B ( Ξ + + c c → Ξ + c π + ) × B ( Ξ + c → p K − π + ) / B ( Ξ + + c c → Λ + c K − π + π + ) × B ( Λ + c → p K − π + ) = 0.035 ± 0.009 ( stat ) ± 0.003 ( syst )
Measurement of the Ωc0 Baryon Lifetime Alfonso Albero, Alejandro; Calvo Gómez, Míriam; Camboni, Alessandro ...
Physical review letters,
08/2018
Journal Article
Recenzirano
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We report a measurement of the lifetime of the Ω 0 c baryon using proton-proton collision data at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3.0 fb − 1 ...collected by the LHCb experiment. The sample consists of about 1000 Ω − b → Ω 0 c μ − ¯ ν μ X signal decays, where the Ω 0 c baryon is detected in the p K − K − π + final state and X represents possible additional undetected particles in the decay. The Ω 0 c lifetime is measured to be τ Ω 0 c = 268 ± 24 ± 10 ± 2 fs , where the uncertainties are statistical, systematic, and from the uncertainty in the D + lifetime, respectively. This value is nearly four times larger than, and inconsistent with, the current world-average value.
Measurement of the Ωc0 Baryon Lifetime Alfonso Albero, Alejandro; Calvo Gómez, Míriam; Camboni, Alessandro ...
Physical review letters,
08/2018
Journal Article
Recenzirano
Odprti dostop
We report a measurement of the lifetime of the Ω 0 c baryon using proton-proton collision data at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3.0 fb − 1 ...collected by the LHCb experiment. The sample consists of about 1000 Ω − b → Ω 0 c μ − ¯ ν μ X signal decays, where the Ω 0 c baryon is detected in the p K − K − π + final state and X represents possible additional undetected particles in the decay. The Ω 0 c lifetime is measured to be τ Ω 0 c = 268 ± 24 ± 10 ± 2 fs , where the uncertainties are statistical, systematic, and from the uncertainty in the D + lifetime, respectively. This value is nearly four times larger than, and inconsistent with, the current world-average value.
The first measurements of the forward-backward asymmetry of the dimuon pair ( A FB ), the triple-product asymmetry ( A 2 ϕ ), and the charge-parity-conjugation asymmetry ( A C P ), in D 0 → π + π − μ ...+ μ − and D 0 → K + K − μ + μ − decays are reported. They are performed using data from proton-proton collisions collected with the LHCb experiment from 2011 to 2016, corresponding to a total integrated luminosity of 5 fb − 1 . The asymmetries are measured to be A FB ( D 0 → π + π − μ + μ − ) = ( 3.3 ± 3.7 ± 0.6 ) % , A 2 ϕ ( D 0 → π + π − μ + μ − ) = ( − 0.6 ± 3.7 ± 0.6 ) % , A C P ( D 0 → π + π − μ + μ − ) = ( 4.9 ± 3.8 ± 0.7 ) % , A FB ( D 0 → K + K − μ + μ − ) = ( 0 ± 11 ± 2 ) % , A 2 ϕ ( D 0 → K + K − μ + μ − ) = ( 9 ± 11 ± 1 ) % , A C P ( D 0 → K + K − μ + μ − ) = ( 0 ± 11 ± 2 ) % , where the first uncertainty is statistical and the second systematic. The asymmetries are also measured as a function of the dimuon invariant mass. The results are consistent with the standard model predictions.
The first measurements of the forward-backward asymmetry of the dimuon pair ( A FB ), the triple-product asymmetry ( A 2 ϕ ), and the charge-parity-conjugation asymmetry ( A C P ), in D 0 → π + π − μ ...+ μ − and D 0 → K + K − μ + μ − decays are reported. They are performed using data from proton-proton collisions collected with the LHCb experiment from 2011 to 2016, corresponding to a total integrated luminosity of 5 fb − 1 . The asymmetries are measured to be A FB ( D 0 → π + π − μ + μ − ) = ( 3.3 ± 3.7 ± 0.6 ) % , A 2 ϕ ( D 0 → π + π − μ + μ − ) = ( − 0.6 ± 3.7 ± 0.6 ) % , A C P ( D 0 → π + π − μ + μ − ) = ( 4.9 ± 3.8 ± 0.7 ) % , A FB ( D 0 → K + K − μ + μ − ) = ( 0 ± 11 ± 2 ) % , A 2 ϕ ( D 0 → K + K − μ + μ − ) = ( 9 ± 11 ± 1 ) % , A C P ( D 0 → K + K − μ + μ − ) = ( 0 ± 11 ± 2 ) % , where the first uncertainty is statistical and the second systematic. The asymmetries are also measured as a function of the dimuon invariant mass. The results are consistent with the standard model predictions.
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