The requirements of the ultra thin pixel detectors for the Mu3e experiment at PSI can be achieved by the HVCMOS technology, which allows the design of fast monolithic detectors. The latest nearly ...full size prototype, MuPix8, has a size of about 1 × 2 cm2. The pixel readout circuitry was fully redesigned in comparison to the previous MuPix versions. MuPix8’s readout electronics implement a new concept with two comparators and two different operation modes. One mode uses two threshold voltages for time walk correction, the other is a ramp-ADC. First tests show a detection efficiency of 99.6% for 4 GeV electrons.
•Large area (1 × 2 cm2) HVCMOS sensor chip with efficiency greater than 99.6%.•New readout electronics with two comparators for each pixel for timewalk correction.•Readout modes: two threshold voltages mode and ADC threshold voltage mode.•Scan logic with pixel groups for a fast search for hits.
High-Voltage Monolithic Active Pixel Sensors (HV-MAPS) based on a 180 nm HV-CMOS process have been proposed to realize thin, fast and highly integrated pixel sensors. The MuPix7 prototype, fabricated ...in the commercial AMS H18 process, features a fully integrated on-chip readout, i.e. hit-digitization, zero suppression and data serialization. MuPix7 is the first fully monolithic HV-CMOS pixel sensor that has been tested for the use in high irradiation environments like HL-LHC. We present results from laboratory and test beam measurements of MuPix7 prototypes irradiated with neutrons (up to 5.0 × 1015 neq/cm2) and 24 GeV protons (up to 7.8 × 1015 protons/cm2) and compare the performance with non-irradiated sensors. At sensor temperatures of about 8 °C efficiencies of ≥90% at noise rates below 40 Hz per pixel are measured for fluences of up to 1.5 × 1015 neq/cm2. A time resolution better than 22 ns, expressed as Gaussian σ, is measured for all tested settings and sensors, even at the highest irradiation fluences. The data transmission at 1.25 Gbit/s and the on-chip PLL remain fully functional.
A measurement is presented of the inclusive neutral current
e
±
p
scattering cross section using data collected by the H1 experiment at HERA during the years 2003 to 2007 with proton beam energies
E
...p
of 920, 575, and 460 GeV. The kinematic range of the measurement covers low absolute four-momentum transfers squared, 1.5 GeV
2
<
Q
2
<120 GeV
2
, small values of Bjorken
x
, 2.9⋅10
−5
<
x
<0.01, and extends to high inelasticity up to
y
=0.85. The structure function
F
L
is measured by combining the new results with previously published H1 data at
E
p
=920 GeV and
E
p
=820 GeV. The new measurements are used to test several phenomenological and QCD models applicable in this low
Q
2
and low
x
kinematic domain.
A new concept, the Triplet Track Trigger (TTT), is proposed for stand-alone tracking at the first trigger level of the FCC-hh detector. The concept is based on a highly scalable monolithic pixel ...sensor technology and uses a very simple and fast track reconstruction algorithm that can be easily implemented in hardware processors. The goal is to suppress the enormous pileup of ~1000 minimum bias collisions expected at the FCC-hh experiment and to identify the hard-interaction vertex and the corresponding tracks as a basis for a trigger decision. In the barrel region, the TTT consists of three closely stacked, highly granular pixel detector layers at radii of ~1m. An extension of the TTT to the endcap region increases the geometrical acceptance. We present full Geant4 simulations and reconstruction performance of a modified FCC-hh reference tracker that includes TTT barrel and endcap detector layers. The stacking of TTT layers results in excellent track purity, and the large lever arm ensures very good momentum resolution. Additionally, sub-mm \(z\)-vertex resolution is achieved, which allows for very efficient pileup suppression. By reconstructing pileup suppressed track-jets, the primary vertex of the hard interaction is successfully identified, even at a pileup rate of \(<\mu>=1000\) and at trigger level. The multi-jet signature, pp->HH->4b, is used as a showcase to study the trigger performance of the TTT and compare it to an emulated calorimeter trigger (calo-trigger). The TTT allows for significantly lower trigger thresholds and higher trigger efficiencies than a calo-trigger. Furthermore, the TTT is very robust against fluctuations in the pileup rate compared to the calo-trigger. As a result, a significant increase in the statistics of di-Higgs events is expected, in particular at low transverse momentum, where the sensitivity to the Higgs self-coupling (\(\lambda\)) is the highest.
The electron-proton collider HERA is being upgraded to provide higher luminosity from the end of the year 2001. In order to enhance the selectivity on exclusive processes a fast track trigger (FTT) ...with high momentum resolution is being built for the H1 collaboration. The FTT will perform a three-dimensional (3-D) reconstruction of curved tracks in a magnetic field of 1.1 Tesla down to 100 MeV in transverse momentum. It is able to reconstruct up to 48 tracks within 23 /spl mu/s in a high track multiplicity environment. The FIT consists of two hardware levels L1, L2 and a third software level. Analog signals of 450 wires are digitized at the first-level stage followed by a quick lookup of valid track segment patterns. For the main processing tasks at the second level such as linking, fitting, and deciding, a multifunctional processing board has been developed by the ETH Zu/spl uml/rich, Switzerland, in collaboration with Supercomputing Systems, Zu/spl uml/rich. It integrates a high-density field programmable gate array (FPGA) and four floating point digital signal processors (DSPs). This presentation will mainly concentrate on second trigger level hardware aspects and on the implementation of the algorithms used for linking and fitting. Emphasis is especially put on the integrated content addressable memory (CAM) functionality of the FPGA, which is ideally suited for implementing fast search tasks like track segment linking.
The parameters of the electroweak theory are determined in a combined electroweak and QCD analysis using all deep-inelastic
e
+
p
and
e
-
p
neutral current and charged current scattering cross ...sections published by the H1 Collaboration, including data with longitudinally polarised lepton beams. Various fits to Standard Model parameters in the on-shell scheme are performed. The mass of the
W
boson is determined as
m
W
=
80.520
±
0.115
GeV
. The axial-vector and vector couplings of the light quarks to the
Z
boson are also determined. Both results improve the precision of previous H1 determinations based on HERA-I data by about a factor of two. Possible scale dependence of the weak coupling parameters in both neutral and charged current interactions beyond the Standard Model is also studied. All results are found to be consistent with the Standard Model expectations.
Sets of parton distribution functions (PDFs) of the proton are reported for the leading (LO), next-to-leading (NLO) and next-to-next-to-leading-order (NNLO) QCD calculations. The parton distribution ...functions are determined with the HERAFitter program using the data from the HERA experiments and preserving correlations between uncertainties for the LO, NLO and NNLO PDF sets. The sets are used to study cross-section ratios and their uncertainties when calculated at different orders in QCD. A reduction of the overall theoretical uncertainty is observed if correlations between the PDF sets are taken into account for the ratio of
W
W
di-boson to
Z
boson production cross sections at the LHC.
Elastic J/ψ production at HERA Aktas, A.; Andreev, V.; Anthonis, T. ...
The European physical journal. C, Particles and fields,
06/2006, Letnik:
46, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Cross sections for elastic production of J/ψ mesons in photoproduction and electroproduction are measured in electron proton collisions at HERA using an integrated luminosity of 55 pb-1. Results are ...presented for photon virtualities Q2 up to 80 GeV2. The dependence on the photon-proton centre of mass energy Wγp is analysed in the range 40≤Wγp≤305 GeV in photoproduction and 40≤Wγp≤160 GeV in electroproduction. The Wγp dependences of the cross sections do not change significantly with Q2 and can be described by models based on perturbative QCD. Within such models, the data show a high sensitivity to the gluon density of the proton in the domain of low Bjorken x and low Q2. Differential cross sections dσ/dt, where t is the squared four-momentum transfer at the proton vertex, are measured in the range |t|<1.2 GeV2 as functions of Wγp and Q2. Effective Pomeron trajectories are determined for photoproduction and electroproduction. The J/ψ production and decay angular distributions are consistent with s-channel helicity conservation. The ratio of the cross sections for longitudinally and transversely polarised photons is measured as a function of Q2 and is found to be described by perturbative QCD based models.
Inclusive charm and beauty cross sections are measured in
e
−
p
and
e
+
p
neutral current collisions at HERA in the kinematic region of photon virtuality 5≤
Q
2
≤2000 GeV
2
and Bjorken scaling ...variable 0.0002≤
x
≤0.05. The data were collected with the H1 detector in the years 2006 and 2007 corresponding to an integrated luminosity of 189 pb
−1
. The numbers of charm and beauty events are determined using variables reconstructed by the H1 vertex detector including the impact parameter of tracks to the primary vertex and the position of the secondary vertex. The measurements are combined with previous data and compared to QCD predictions.
Inclusive e(+/-)p single and double differential cross sections for neutral and charged current deep inelastic scattering processes are measured with the H1 detector at HERA. The data were taken at a ...centre-of-mass energy of root s = 319 GeV with a total integrated luminosity of 333.7 pb(-1) shared between two lepton beam charges and two longitudinal lepton polarisation modes. The differential cross sections are measured in the range of negative four-momentum transfer squared, Q(2), between 60 and 50 000GeV(2), and Bjorken x between 0.0008 and 0.65. The measurements are combined with earlier published unpolarised H1 data to improve statistical precision and used to determine the structure function xF(3)(gamma Z). A measurement of the neutral current parity violating structure function F-2(gamma Z) is presented for the first time. The polarisation dependence of the charged current total cross section is also measured. The new measurements are well described by a next-to-leading order QCD fit based on all published H1 inclusive cross section data which are used to extract the parton distribution functions of the proton.
PDF
