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Caroline Collard

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DOI: 10.1016/j.physletb.2003.08.048
2003
Cited 158 times
Measurement of deeply virtual Compton scattering at HERA
The cross-section for deeply virtual Compton scattering in the reaction ep→eγp has been measured with the ZEUS detector at HERA using integrated luminosities of 95.0 pb−1 of e+p and 16.7 pb−1 of e−p collisions. Differential cross-sections are presented as a function of the exchanged-photon virtuality, Q2, and the centre-of-mass energy, W, of the γ∗p system in the region 5<Q2<100 GeV2 and 40<W<140 GeV. The measured cross-sections rise steeply with increasing W. The measurements are compared to QCD-based calculations.
DOI: 10.1016/s0370-2693(01)00939-x
2001
Cited 146 times
Measurement of deeply virtual Compton scattering at HERA
A measurement is presented of elastic deeply virtual Compton scattering e++p→e++γ+p at HERA using data taken with the H1 detector. The cross section is measured as a function of the photon virtuality, Q2, and the invariant mass, W, of the γp system, in the kinematic range 2<Q2<20GeV2, 30<W<120GeV and |t|<1GeV2, where t is the squared momentum transfer to the proton. The measurement is compared to QCD based calculations.
DOI: 10.1016/j.physletb.2004.03.012
2004
Cited 131 times
Evidence for a narrow anti-charmed baryon state
A narrow resonance in D∗−p and D∗+p̄ invariant mass combinations is observed in inelastic electron–proton collisions at centre-of-mass energies of 300 GeV and 320 GeV at HERA. The resonance has a mass of 3099±3(stat.)±5(syst.) MeV and a measured Gaussian width of 12±3(stat.) MeV, compatible with the experimental resolution. The resonance is interpreted as an anti-charmed baryon with a minimal constituent quark composition of uuddc̄, together with the charge conjugate.
DOI: 10.1088/1748-0221/16/02/p02027
2021
Cited 34 times
The CMS Phase-1 pixel detector upgrade
The CMS detector at the CERN LHC features a silicon pixel detector as its innermost subdetector. The original CMS pixel detector has been replaced with an upgraded pixel system (CMS Phase-1 pixel detector) in the extended year-end technical stop of the LHC in 2016/2017. The upgraded CMS pixel detector is designed to cope with the higher instantaneous luminosities that have been achieved by the LHC after the upgrades to the accelerator during the first long shutdown in 2013–2014. Compared to the original pixel detector, the upgraded detector has a better tracking performance and lower mass with four barrel layers and three endcap disks on each side to provide hit coverage up to an absolute value of pseudorapidity of 2.5. This paper describes the design and construction of the CMS Phase-1 pixel detector as well as its performance from commissioning to early operation in collision data-taking.
DOI: 10.1038/s41597-022-01532-x
2022
Cited 21 times
Cytopathic SARS-CoV-2 screening on VERO-E6 cells in a large-scale repurposing effort
Worldwide, there are intensive efforts to identify repurposed drugs as potential therapies against SARS-CoV-2 infection and the associated COVID-19 disease. To date, the anti-inflammatory drug dexamethasone and (to a lesser extent) the RNA-polymerase inhibitor remdesivir have been shown to be effective in reducing mortality and patient time to recovery, respectively, in patients. Here, we report the results of a phenotypic screening campaign within an EU-funded project (H2020-EXSCALATE4COV) aimed at extending the repertoire of anti-COVID therapeutics through repurposing of available compounds and highlighting compounds with new mechanisms of action against viral infection. We screened 8702 molecules from different repurposing libraries, to reveal 110 compounds with an anti-cytopathic IC50 < 20 µM. From this group, 18 with a safety index greater than 2 are also marketed drugs, making them suitable for further study as potential therapies against COVID-19. Our result supports the idea that a systematic approach to repurposing is a valid strategy to accelerate the necessary drug discovery process.
DOI: 10.1016/s0370-2693(01)01074-7
2001
Cited 103 times
On the rise of the proton structure function F2 towards low x
A measurement of the derivative (d ln F_2 / d lnx)_(Q^2)= -lambda(x,Q^2) of the proton structure function F_2 is presented in the low x domain of deeply inelastic positron-proton scattering. For 5*10^(-5)<=x<=0.01 and Q^2>=1.5 GeV^2, lambda(x,Q^2) is found to be independent of x and to increase linearly with ln(Q^2).
DOI: 10.1016/s0370-2693(02)01195-4
2002
Cited 100 times
Measurement of D meson production and F2 in deep-inelastic scattering at HERA
The inclusive production of D∗±(2010) mesons in deep-inelastic scattering is studied with the H1 detector at HERA. In the kinematic region 1<Q2<100 GeV2 and 0.05<y<0.7 an e+p cross section for inclusive D∗± meson production of 8.50±0.42(stat.)+1.21−1.00(syst.) nb is measured in the visible range ptD∗>1.5 GeV and |ηD∗|<1.5. Single and double differential inclusive D∗± meson cross sections are compared to perturbative QCD calculations in two different evolution schemes. The charm contribution to the proton structure, F2c(x,Q2), is determined by extrapolating the visible charm cross section to the full phase space. This contribution is found to rise from about 10% at Q2=1.5 GeV2 to more than 25% at Q2=60 GeV2 corresponding to x values ranging from 5×10−5 to 3×10−3.
DOI: 10.1016/s0370-2693(99)01099-0
1999
Cited 84 times
Measurement of open beauty production at HERA
The first observation of open b production in ep collisions is reported. An event sample containing muons and jets has been selected which is enriched in semileptonic b quark decays. The visible cross section σ(ep→bb̄X→μX′)for Q2<1GeV2, 0.1<y<0.8 is measured to be 0.176±0.016(stat.)+0.026−0.017(syst.)nb for the muons to be detected in the range 35°<θμ<130° and p⊥μ>2.0GeV in the laboratory frame. The expected visible cross section based on a NLO QCD calculation is 0.104±0.017nb. The cross sections for electroproduction with Q2<1GeV2 and photoproduction are derived from the data and found to be σ(ep→ebb̄X)=7.1±0.6(stat.)+1.5−1.3(syst.)nb and σ(γp→bb̄X)=111±10(stat.)+23−20(syst.)nb at an average 〈Wγp〉∼180GeV, respectively.
DOI: 10.1016/s0370-2693(02)02275-x
2002
Cited 69 times
Diffractive photoproduction of ψ(2S) mesons at HERA
Results on diffractive photoproduction of ψ(2S) mesons are presented using data collected between 1996 and 2000 with the H1 detector at the HERA ep collider. The data correspond to an integrated luminosity of 77 pb−1. The energy dependence of the diffractive ψ(2S) cross section is found to be similar to or possibly somewhat steeper than that for J/ψ mesons. The dependences of the elastic and proton dissociative ψ(2S) photoproduction cross sections on the squared momentum transfer t at the proton vertex are measured. The t-dependence of the elastic channel, parametrised as ebt, yields belψ(2S)=(4.31±0.57±0.46) GeV−2, compatible with that of the J/ψ. For the proton dissociative channel the result bpdψ(2S)=(0.59±0.13±0.12) GeV−2 is 2.3 standard deviations smaller than that measured for the J/ψ. With proper account of the individual wavefunctions theoretical predictions based on perturbative QCD are found to describe the measurements well.
DOI: 10.1007/jhep03(2011)024
2011
Cited 46 times
Search for heavy stable charged particles in pp collisions at $ \sqrt {s} = 7\;{\text{TeV}} $
The result of a search at the LHC for heavy stable charged particles produced in pp collisions at $ \sqrt {s} = 7\;{\text{TeV}} $ is described. The data sample was collected with the CMS detector and corresponds to an integrated luminosity of 3.1 pb−1. Momentum and ionization-energy-loss measurements in the inner tracker detector are used to identify tracks compatible with heavy slow-moving particles. Additionally, tracks passing muon identification requirements are also analyzed for the same signature. In each case, no candidate passes the selection, with an expected background of less than 0.1 events. A lower limit at the 95% confidence level on the mass of a stable gluino is set at 398GeV/c 2, using a conventional model of nuclear interactions that allows charged hadrons containing this particle to reach the muon detectors. A lower limit of 311 GeV/c 2 is also set for a stable gluino in a conservative scenario of complete charge suppression, where any hadron containing this particle becomes neutral before reaching the muon detectors.
DOI: 10.1016/j.physletb.2011.03.060
2011
Cited 43 times
First measurement of hadronic event shapes in pp collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>7</mml:mn><mml:mtext> </mml:mtext><mml:mtext>TeV</mml:mtext></mml:math>
Hadronic event shapes have been measured in proton-proton collisions at sqrt(s)=7 TeV, with a data sample collected with the CMS detector at the LHC. The sample corresponds to an integrated luminosity of 3.2 inverse picobarns. Event-shape distributions, corrected for detector response, are compared with five models of QCD multijet production.
DOI: 10.1140/epjc/s10052-011-1721-3
2011
Cited 42 times
Measurement of the $\mathrm{{t\bar{t}}}$ production cross section in pp collisions at $\sqrt{s}=7$ TeV using the kinematic properties of events with leptons and jets
A measurement of the top-antitop production cross section in proton-proton collisions at a centre-of-mass energy of 7 TeV has been performed at the LHC with the CMS detector. The analysis uses a data sample corresponding to an integrated luminosity of 36 inverse picobarns and is based on the reconstruction of the final state with one isolated, high transverse-momentum electron or muon and three or more hadronic jets. The kinematic properties of the events are used to separate the top-antitop signal from W+jets and QCD multijet background events. The measured cross section is 173 + 39 - 32 (stat. + syst.) pb, consistent with standard model expectations.
DOI: 10.1103/physrevd.93.034014
2016
Cited 32 times
Measurement of the charge asymmetry in top quark pair production inppcollisions ats=8 TeVusing a template method
The charge asymmetry in the production of top quark and antiquark pairs is measured in proton-proton collisions at a center-of-mass energy of 8 TeV. The data, corresponding to an integrated luminosity of 19.6 inverse femtobarns, were collected by the CMS experiment at the LHC. Events with a single isolated electron or muon, and four or more jets, at least one of which is likely to have originated from hadronization of a bottom quark, are selected. A template technique is used to measure the asymmetry in the distribution of differences in the top quark and antiquark absolute rapidities. The measured asymmetry is A[c,y] = [0.33 +/- 0.26 (stat) +/- 0.33 (syst)]%, which is the most precise result to date. The results are compared to calculations based on the standard model and on several beyond-the-standard-model scenarios.
DOI: 10.1016/s0370-2693(00)00613-4
2000
Cited 63 times
Measurement of elastic electroproduction of mesons at HERA
The elastic electroproduction of φ mesons is studied at HERA with the H1 detector for photon virtualities 1<Q2<15GeV2 and hadronic centre of mass energies 40<W<130 GeV. The Q2 and t dependences of the cross section are extracted (t being the square of the four-momentum transfer to the target proton). When plotted as function of (Q2 + MV2) and scaled by the appropriate SU(5) quark charge factor, the φ meson cross section agrees within errors with the cross sections of the vector mesons V = ρ, ω and J/ψ. A detailed analysis is performed of the φ meson polarisation state and the ratio of the production cross sections for longitudinally and transversely polarised φ mesons is determined. A small but significant violation of s-channel helicity conservation (SCHC) is observed.
DOI: 10.1140/epjc/s2004-02069-x
2005
Cited 54 times
Inclusive production of D + , D 0, D s + and D * + mesonsin deep inelastic scattering at HERA
Inclusive production cross sections are measured in deep inelastic scattering at HERA for meson states composed of a charm quark and a light antiquark or the charge conjugate.The measurements cover the kinematic region of photon virtuality 2 < Q 2 < 100 GeV 2 , inelasticity 0.05 < y < 0.7, D meson transverse momenta p t (D) ≥ 2.5 GeV and pseudorapidity |η(D)| ≤ 1.5.The identification of the D-meson decays and the reduction of the combinatorial background profit from the reconstruction of displaced secondary vertices by means of the H1 silicon vertex detector.The production of charmed mesons containing the light quarks u, d and s is found to be compatible with a description in which the hard scattering is followed by a factorisable and universal hadronisation process.
DOI: 10.1016/j.physletb.2003.06.056
2003
Cited 48 times
Diffractive photoproduction of J/ψ mesons with large momentum transfer at HERA
The diffractive photoproduction of J/psi mesons is measured with the H1 detector at the ep collider HERA using an integrated luminosity of 78 pb^-1. The differential cross section d sigma(gamma p -> J/psi Y) / d t is studied in the range 2 < |t| < 30 GeV^2, where t is the square of the four-momentum transferred at the proton vertex. The cross section is also presented as a function of the photon-proton centre-of-mass energy W in three t intervals, spanning the range 50 < W < 200 GeV. A fast rise of the cross section with W is observed for each t range and the slope for the effective linear Pomeron trajectory is measured to be alpha^\prime= -0.0135 \pm 0.0074 (stat.) \pm 0.0051 (syst.) GeV^-2. The measurements are compared with perturbative QCD models based on BFKL and DGLAP evolution. The data are found to be compatible with s-channel helicity conservation.
DOI: 10.1140/epjc/s2003-01588-2
2004
Cited 45 times
Search for single top quark production in ep collisions at HERA
A search for single top quark production is performed in e^\pm p collisions at HERA. The search exploits data corresponding to an integrated luminosity of 118.3 pb^-1. A model for the anomalous production of top quarks in a flavour changing neutral current process involving a t-u-gamma coupling is investigated. Decays of top quarks into a b quark and a W boson are considered in the leptonic and the hadronic decay channels of the W. Both a cut-based analysis and a multivariate likelihood analysis are performed to discriminate anomalous top quark production from Standard Model background processes. In the leptonic channel, 5 events are found while 1.31 \pm 0.22 events are expected from the Standard Model background. In the hadronic channel, no excess above the expectation for Standard Model processes is found. These observations lead to a cross section \sigma (ep -> e t X) = 0.29 +0.15 -0.14 pb at \sqrt{s} = 319 GeV. Alternatively, assuming that the observed events are due to a statistical fluctuation, upper limits of 0.55 pb on the anomalous top production cross section and of 0.27 on the t-u-gamma coupling \kappa_{t-u-gamma} are established at the 95% confidence level.
DOI: 10.1140/epjcd/s2006-02-002-x
2006
Cited 45 times
Reconstruction of the signal amplitude of the CMS electromagnetic calorimeter
The amplitude of the signal collected from the PbWO4 crystals of the CMS electromagnetic calorimeter is reconstructed by a digital filtering technique. The amplitude reconstruction has been studied with test beam data recorded from a fully equipped barrel supermodule. Issues specific to data taken in the test beam are investigated, and the implementation of the method for CMS data taking is discussed.
2006
Cited 41 times
CP Studies and Non-Standard Higgs Physics
There are many possibilities for new physics beyond the Standard Model that feature non-standard Higgs sectors. These may introduce new sources of CP violation, and there may be mixing between multiple Higgs bosons or other new scalar bosons. Alternatively, the Higgs may be a composite state, or there may even be no Higgs at all. These non-standard Higgs scenarios have important implications for collider physics as well as for cosmology, and understanding their phenomenology is essential for a full comprehension of electroweak symmetry breaking. This report discusses the most relevant theories which go beyond the Standard Model and its minimal, CP-conserving supersymmetric extension: two-Higgs-doublet models and minimal supersymmetric models with CP violation, supersymmetric models with an extra singlet, models with extra gauge groups or Higgs triplets, Little Higgs models, models in extra dimensions, and models with technicolour or other new strong dynamics. For each of these scenarios, this report presents an introduction to the phenomenology, followed by contributions on more detailed theoretical aspects and studies of possible experimental signatures at the LHC and other colliders.
DOI: 10.1088/1748-0221/5/09/p09003
2010
Cited 36 times
Performance of the electronic readout of the ATLAS liquid argon calorimeters
The ATLAS detector has been designed for operation at the Large Hadron Collider at CERN. ATLAS includes electromagnetic and hadronic liquid argon calorimeters, with almost 200,000 channels of data that must be sampled at the LHC bunch crossing frequency of 40 MHz. The calorimeter electronics calibration and readout are performed by custom electronics developed specifically for these purposes. This paper describes the system performance of the ATLAS liquid argon calibration and readout electronics, including noise, energy and time resolution, and long term stability, with data taken mainly from full-system calibration runs performed after installation of the system in the ATLAS detector hall at CERN.
DOI: 10.1016/s0370-2693(03)00497-0
2003
Cited 39 times
Isolated electrons and muons in events with missing transverse momentum at HERA
A search for events with a high-energy isolated electron or muon and missing transverse momentum has been performed at the electron–proton collider HERA using an integrated luminosity of 13.6 pb−1 in e−p scattering and 104.7 pb−1 in e+p scattering. Within the Standard Model such events are expected to be mainly due to W boson production with subsequent leptonic decay. In e−p interactions one event is observed in the electron channel and none in the muon channel, consistent with the expectation of the Standard Model. In the e+p data a total of 18 events are seen in the electron and muon channels compared to an expectation of 12.4±1.7 dominated by W production (9.4±1.6). Whilst the overall observed number of events is broadly in agreement with the number predicted by the Standard Model, there is an excess of events with transverse momentum of the hadronic system greater than 25 GeV with 10 events found compared to 2.9±0.5 expected. The results are used to determine the cross-section for events with an isolated electron or muon and missing transverse momentum.
DOI: 10.1016/s0370-2693(00)00332-4
2000
Cited 41 times
Search for compositeness, leptoquarks and large extra dimensions in eq contact interactions at HERA
The reaction e+p→e+X is studied with the H1 detector at Hera. The data cover momentum transfers Q2 between 200GeV2 and 30000GeV2 and correspond to an integrated luminosity of 35.6pb−1. The differential cross section dσ/dQ2 is compared to the Standard Model expectation for neutral current scattering and analysed to search for (ēe)(q̄q) contact interactions. No evidence for new phenomena is observed. The results are used to set limits on scales within models of electron–quark compositeness, quark form factors and the exchange of virtual heavy leptoquarks. A search for gravitational effects mediated through the exchange of virtual gravitons which propagate into large extra dimensions is presented.
DOI: 10.1016/j.physletb.2005.09.048
2005
Cited 34 times
Search for leptoquark bosons in ep collisions at HERA
A search for scalar and vector leptoquarks coupling to first generation fermions is performed using the e+p and e−p scattering data collected by the H1 experiment between 1994 and 2000. The data correspond to a total integrated luminosity of 117pb−1. No evidence for the direct or indirect production of such particles is found in data samples with a large transverse momentum final state electron or with large missing transverse momentum. Constraints on leptoquark models are established. For leptoquark couplings of electromagnetic strength, leptoquarks with masses up to 275–325GeV are ruled out at 95% confidence level. These limits improve and supercede earlier H1 limits based on subsamples of the data used here.
DOI: 10.1140/epjc/s2004-01644-5
2004
Cited 33 times
Inclusive dijet production at low Bjorken-x in deep inelastic scattering
Dijet production in deep inelastic ep scattering is investigated in the region of low values of the Bjorken-variable x (10 -4 < x < 10 -2 ) and low photon virtualities Q 2 (5 < Q 2 < 100 GeV 2 ).The measured dijet cross sections are compared with perturbative QCD calculations in next-to-leading order.For most dijet variables studied, these calculations can provide a reasonable description of the data over the full phase space region covered, including the region of very low x.However, large discrepancies are observed for events with small separation in azimuth between the two highest transverse momentum jets.This region of phase space is described better by predictions based on the CCFM evolution equation, which incorporates k t factorized unintegrated parton distributions.A reasonable description is also obtained using the Color Dipole Model or models incorporating virtual photon structure.
DOI: 10.1140/epjcd/s2005-02-011-3
2006
Cited 31 times
Results of the first performance tests * of the CMS electromagnetic calorimeter
Performance tests of some aspects of the CMS ECAL were carried out on modules of the "barrel" sub-system in 2002 and 2003. A brief test with high energy electron beams was made in late 2003 to validate prototypes of the new Very Front End electronics. The final versions of the monitoring and cooling systems, and of the high and low voltage regulation were used in these tests. The results are consistent with the performance targets including those for noise and overall energy resolution, required to fulfil the physics programme of CMS at the LHC.
DOI: 10.1016/s0370-2693(02)02375-4
2002
Cited 32 times
Measurement of inclusive jet cross-sections in deep-inelastic ep scattering at HERA
A measurement of inclusive jet cross-sections in deep-inelastic ep scattering at HERA is presented based on data with an integrated luminosity of 21.1 pb−1. The measurement is performed for photon virtualities Q2 between 5 and 100 GeV2, differentially in Q2, in the jet transverse energy ET, in ET2/Q2 and in the pseudorapidity ηlab. With the renormalization scale μR=ET, perturbative QCD calculations in next-to-leading order (NLO) give a good description of the data in most of the phase space. Significant discrepancies are observed only for jets in the proton beam direction with ET below 20 GeV and Q2 below 20 GeV2. This corresponds to the region in which NLO corrections are largest and further improvement of the calculations is thus of particular interest.
DOI: 10.1103/physrevc.71.034307
2005
Cited 28 times
Intruder structures observed in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">Te</mml:mi><mml:mprescripts /><mml:none /><mml:mrow><mml:mn>122</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>through inelastic neutron scattering
The excited levels of $^{122}\mathrm{Te}$ to $3.3\ensuremath{-}\phantom{\rule{0.3em}{0ex}}\text{MeV}$ excitation have been studied using $\ensuremath{\gamma}$-ray spectroscopy following inelastic neutron scattering. The decay characteristics of these levels have been determined from $\ensuremath{\gamma}$-ray excitation functions, angular distributions at ${E}_{n}\ensuremath{-}1.72,2.80$, and $3.35\phantom{\rule{0.3em}{0ex}}\text{MeV}$, Doppler shifts, and $\ensuremath{\gamma}\ensuremath{\gamma}$ coincidences. Electromagnetic transition rates were deduced for many levels, as were multipole-mixing and branching ratios. Level energies and electromagnetic transition rates were compared to interacting boson model (IBM) calculations, both with and without intruder-state mixing, and to particle-core coupling model calculations. The energies of low-lying levels of $^{122}\mathrm{Te}$ are well described by the IBM with intruder-state mixing calculations, and observed transition rates support emerging intruder bands built on ${0}^{+}$ levels. The other models considered do not produce enough low-lying positive parity states; however, U(5) energies to the four quadrupole-phonon level agree very well with observations when states with large intruder configurations are ignored. Mixed-symmetry and quadrupole-octupole excitations have been investigated, but mixing with other configurations and fragmentation of strength prohibit a clear identification of these states.
DOI: 10.1016/j.physletb.2003.06.034
2003
Cited 28 times
Search for new physics in e±q contact interactions at HERA
Deep-inelastic e±p scattering at high squared momentum transfer Q2 up to 30 000 GeV2 is used to search for eq contact interactions associated to scales far beyond the Hera centre of mass energy. The neutral current cross section measurements dσ/dQ2, corresponding to integrated luminosities of 16.4 pb−1 of e−p data and 100.8 pb−1 of e+p data, are well described by the Standard Model and are analysed to set constraints on new phenomena. For conventional contact interactions lower limits are set on compositeness scales Λ ranging between 1.6–5.5 TeV. Couplings and masses of leptoquarks and squarks in R-parity violating supersymmetry are constrained to M/λ>0.3–1.4 TeV. A search for low scale quantum gravity effects in models with large extra dimensions provides limits on the effective Planck scale of MS>0.8 TeV. A form factor analysis yields a bound on the radius of light quarks of Rq<1.0×10−18 m.
DOI: 10.1140/epjc/s10052-012-1965-6
2012
Cited 15 times
Search for decays of stopped, long-lived particles from 7 TeV pp collisions with the ATLAS detector
New metastable massive particles with electric and colour charge are features of many theories beyond the Standard Model. A search is performed for long-lived gluino-based R-hadrons with the ATLAS detector at the LHC using a data sample corresponding to an integrated luminosity of 31 pb−1. We search for evidence of particles that have come to rest in the ATLAS detector and decay at some later time during the periods in the LHC bunch structure without proton–proton collisions. No significant deviations from the expected backgrounds are observed, and a cross-section limit is set. It can be interpreted as excluding gluino-based R-hadrons with masses less than 341 GeV at the 95 % C.L., for lifetimes from 10−5 to 103 seconds and a neutralino mass of 100 GeV.
DOI: 10.1016/s0370-2693(01)00805-x
2001
Cited 26 times
Three-jet production in deep-inelastic scattering at HERA
Three-jet production is studied for the first time in deep-inelastic positron-proton scattering. The measurement carried out with the H1 detector at HERA covers a large range of four-momentum transfer squared 5 < Q^2 < 5000 GeV^2 and invariant three-jet masses 25 < M_(3jet) < 140 GeV. Jets are defined by the inclusive k_T algorithm in the Breit frame. The size of the three-jet cross section and the ratio of the three-jet to the dijet cross section R_(3/2) are described over the whole phase space by the predictions of perturbative QCD in next-to-leading order. The shapes of angular jet distributions deviate significantly from a uniform population of the available phase space but are well described by the QCD calculation.
DOI: 10.1016/s0370-2693(02)02479-6
2002
Cited 23 times
Search for odderon-induced contributions to exclusive π0 photoproduction at HERA
A search for contributions to the reaction ep→eπ0N∗ from photon–odderon fusion in the photoproduction regime at HERA is reported, at an average photon–proton centre-of-mass energy 〈W〉=215 GeV. The measurement proceeds via detection of the π0 decay photons, a leading neutron from the N∗ decay, and the scattered electron. No π0 signal is observed and an upper limit on the cross section for the photon–odderon fusion process of σ(γp→π0N∗)<49 nb at the 95% confidence level is derived, integrated over the experimentally accessible range of the squared four-momentum transfer at the nucleon vertex 0.02<|t|<0.3 GeV2. This excludes a recent prediction from a calculation based on a non-perturbative QCD model of a photon–odderon fusion cross section above 200 nb.
DOI: 10.1016/s0370-2693(02)02035-x
2002
Cited 23 times
A measurement of the t dependence of the helicity structure of diffractive ρ meson electroproduction at HERA
The helicity structure of the diffractive electroproduction of ρ mesons, e+p→e+ρ+Y, is studied in a previously unexplored region of large four-momentum transfer squared at the proton vertex, t: 0<t′<3 GeV2, where t′=|t|−|t|min. The data used are collected with the H1 detector at HERA in the kinematic domain 2.5<Q2<60 GeV2, 40<W<120 GeV. No t dependence of the r0400 spin density matrix element is found. A significant t dependent helicity non-conservation from the virtual photon to the ρ meson is observed for the spin density matrix element combinations r500+2r511 and r100+2r111. These t dependences are consistently described by a perturbative QCD model based on the exchange of two gluons.
DOI: 10.1140/epjc/s2004-02085-x
2005
Cited 22 times
Measurement of prompt photon cross sections in photoproduction at HERA
Results are presented on the photoproduction of isolated prompt photons, inclusively and associated with jets, in the γp center of mass energy range 142 < W < 266 GeV.The cross sections are measured for the transverse momentum range of the photons 5 < E γ T < 10 GeV and for associated jets with E jet T > 4.5 GeV.They are measured differentially as a function of E γ T , E jet T , the pseudorapidities η γ and η jet and estimators of the momentum fractions x γ and x p of the incident photon and proton carried by the constituents participating in the hard process.In order to further investigate the underlying dynamics, the angular correlation between the prompt photon and the jet in the transverse plane is studied.Predictions by perturbative QCD calculations in next to leading order are about 30% below the inclusive prompt photon data after corrections for hadronisation and multiple interactions, but are in reasonable agreement with the results for prompt photons associated with jets.Comparisons with the predictions of the event generators PYTHIA and HERWIG are also presented.
DOI: 10.48550/arxiv.hep-ph/0608079
2006
Cited 21 times
CP Studies and Non-Standard Higgs Physics
There are many possibilities for new physics beyond the Standard Model that feature non-standard Higgs sectors. These may introduce new sources of CP violation, and there may be mixing between multiple Higgs bosons or other new scalar bosons. Alternatively, the Higgs may be a composite state, or there may even be no Higgs at all. These non-standard Higgs scenarios have important implications for collider physics as well as for cosmology, and understanding their phenomenology is essential for a full comprehension of electroweak symmetry breaking. This report discusses the most relevant theories which go beyond the Standard Model and its minimal, CP-conserving supersymmetric extension: two-Higgs-doublet models and minimal supersymmetric models with CP violation, supersymmetric models with an extra singlet, models with extra gauge groups or Higgs triplets, Little Higgs models, models in extra dimensions, and models with technicolour or other new strong dynamics. For each of these scenarios, this report presents an introduction to the phenomenology, followed by contributions on more detailed theoretical aspects and studies of possible experimental signatures at the LHC and other colliders.
DOI: 10.1016/j.physletb.2004.01.003
2004
Cited 21 times
Muon pair production in ep collisions at HERA
Cross sections for the production of two isolated muons up to high di-muon masses are measured in ep collisions at HERA with the H1 detector in a data sample corresponding to an integrated luminosity of 71 pb−1 at a centre of mass energy of s=319 GeV. The results are in good agreement with Standard Model predictions, the dominant process being photon–photon interactions. Additional muons or electrons are searched for in events with two high transverse momentum muons using the full data sample corresponding to 114 pb−1, where data at s=301 GeV and s=319 GeV are combined. Both the di-lepton sample and the tri-lepton sample agree well with the predictions.
DOI: 10.1088/1748-0221/16/12/p12014
2021
Cited 8 times
Comparative evaluation of analogue front-end designs for the CMS Inner Tracker at the High Luminosity LHC
Abstract The CMS Inner Tracker, made of silicon pixel modules, will be entirely replaced prior to the start of the High Luminosity LHC period. One of the crucial components of the new Inner Tracker system is the readout chip, being developed by the RD53 Collaboration, and in particular its analogue front-end, which receives the signal from the sensor and digitizes it. Three different analogue front-ends (Synchronous, Linear, and Differential) were designed and implemented in the RD53A demonstrator chip. A dedicated evaluation program was carried out to select the most suitable design to build a radiation tolerant pixel detector able to sustain high particle rates with high efficiency and a small fraction of spurious pixel hits. The test results showed that all three analogue front-ends presented strong points, but also limitations. The Differential front-end demonstrated very low noise, but the threshold tuning became problematic after irradiation. Moreover, a saturation in the preamplifier feedback loop affected the return of the signal to baseline and thus increased the dead time. The Synchronous front-end showed very good timing performance, but also higher noise. For the Linear front-end all of the parameters were within specification, although this design had the largest time walk. This limitation was addressed and mitigated in an improved design. The analysis of the advantages and disadvantages of the three front-ends in the context of the CMS Inner Tracker operation requirements led to the selection of the improved design Linear front-end for integration in the final CMS readout chip.
DOI: 10.1016/s0370-2693(00)00576-1
2000
Cited 24 times
Measurement of di-jet cross-sections in photoproduction and photon structure
The production of hard di-jet events in photoproduction at HERA is dominated by resolved photon processes in which a parton in the photon with momentum fraction xγ is scattered from a parton in the proton. These processes are sensitive to the quark and gluon content of the photon. The differential di-jet cross-section dσ/dlog(xγ) is presented here, measured in tagged photoproduction at HERA using data taken with the H1 detector, corresponding to an integrated luminosity of 7.2 pb−1. Using a restricted data sample at high transverse jet energy, ET,jet>6 GeV, the effective parton density fγ,eff(xγ)=q(xγ)+q̄(xγ)+9/4g(xγ) in the photon in leading order QCD is measured down to xγ= 0.05 from which the gluon density in the photon is derived.
DOI: 10.1140/epjc/s2003-01262-9
2003
Cited 19 times
Measurement of inclusive jet cross sections in photoproduction at HERA
Inclusive jet cross sections are measured in photoproduction at HERA using the H1 detector. The data sample of e+ p -> e+ + jet + X events in the kinematic range of photon virtualities Q^2 < 1 GeV^2 and photon-proton centre-of-mass energies 95 < W_gammap < 285 GeV represents an integrated luminosity of 24.1 pb^-1. Jets are defined using the inclusive k_T algorithm. Single- and multi-differential cross sections are measured as functions of jet transverse energy E_T^jet and pseudorapidity \eta^jet in the domain 5 < E_T^jet < 75 GeV and -1 < \eta^jet < 2.5. The cross sections are found to be in good agreement with next-to-leading order perturbative QCD calculations corrected for fragmentation and underlying event effects. The cross section differential in E_T^jet, which varies by six orders of magnitude over the measured range, is compared with similar distributions from p pbar colliders at equal and higher energies.
DOI: 10.1016/j.nima.2023.168326
2023
Evaluation of HPK <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="d1e1449" altimg="si31.svg"><mml:mrow><mml:msup><mml:mrow><mml:mi>n</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:mtext>-</mml:mtext><mml:mi>p</mml:mi></mml:mrow></mml:math> planar pixel sensors for the CMS Phase-2 upgrade
To cope with the challenging environment of the planned high luminosity upgrade of the Large Hadron Collider (HL-LHC), scheduled to start operation in 2029, CMS will replace its entire tracking system. The requirements for the tracker are largely determined by the long operation time of 10 years with an instantaneous peak luminosity of up to 7.5 × 1034 cm−2 s−1 in the ultimate performance scenario. Depending on the radial distance from the interaction point, the silicon sensors will receive a particle fluence corresponding to a non-ionising energy loss of up to Φeq= 3.5 × 1016 cm−2. This paper focuses on planar pixel sensor design and qualification up to a fluence of Φeq = 1.4 × 1016 cm−2.For the development of appropriate planar pixel sensors an R&D program was initiated, which includes n+-p sensors on 150 mm (6”) wafers with an active thickness of 150 µm with pixel sizes of 100×25 µm2 and 50×50 µm2 manufactured by Hamamatsu Photonics K.K. (HPK). Single chip modules with ROC4Sens and RD53A readout chips were made. Irradiation with protons and neutrons, as well was an extensive test beam campaign at DESY were carried out. This paper presents the investigation of various assemblies mainly with ROC4Sens readout chips. It demonstrates that multiple designs fulfil the requirements in terms of breakdown voltage, leakage current and efficiency. The single point resolution for 50×50 µm2 pixels is measured as 4.0 µm for non-irradiated samples, and 6.3 µm after irradiation to Φeq = 7.2 × 1015 cm−2.
DOI: 10.1088/1748-0221/18/11/p11015
2023
Evaluation of planar silicon pixel sensors with the RD53A readout chip for the Phase-2 Upgrade of the CMS Inner Tracker
Abstract The Large Hadron Collider at CERN will undergo an upgrade in order to increase its luminosity to 7.5 × 10 34 cm -2 s -1 . The increased luminosity during this High-Luminosity running phase, starting around 2029, means a higher rate of proton-proton interactions, hence a larger ionizing dose and particle fluence for the detectors. The current tracking system of the CMS experiment will be fully replaced in order to cope with the new operating conditions. Prototype planar pixel sensors for the CMS Inner Tracker with square 50 μm × 50 μm and rectangular 100 μm × 25 μm pixels read out by the RD53A chip were characterized in the lab and at the DESY-II testbeam facility in order to identify designs that meet the requirements of CMS during the High-Luminosity running phase. A spatial resolution of approximately 3.4 μm (2 μm) is obtained using the modules with 50 μm × 50 μm (100 μm × 25 μm) pixels at the optimal angle of incidence before irradiation. After irradiation to a 1 MeV neutron equivalent fluence of Φ eq = 5.3 × 10 15 cm -2 , a resolution of 9.4 μm is achieved at a bias voltage of 800 V using a module with 50 μm × 50 μm pixel size. All modules retain a hit efficiency in excess of 99% after irradiation to fluences up to 2.1 × 10 16 cm -2 . Further studies of the electrical properties of the modules, especially crosstalk, are also presented in this paper.
DOI: 10.1007/s100520100716
2001
Cited 20 times
Searches at HERA for squarks in R-parity violating supersymmetry
A search for squarks in R-parity violating supersymmetry is performed in $e^+ p$ collisions at HERA at a centre of mass energy of 300 GeV, using H1 data corresponding to an integrated luminosity of 37 pb $^{-1}$ . The direct production of single squarks of any generation in positron-quark fusion via a Yukawa coupling $\lambda'$ is considered, taking into account R-parity violating and conserving decays of the squarks. No significant deviation from the Standard Model expectation is found. The results are interpreted in terms of constraints within the Minimal Supersymmetric Standard Model (MSSM), the constrained MSSM and the minimal Supergravity model, and their sensitivity to the model parameters is studied in detail. For a Yukawa coupling of electromagnetic strength, squark masses below 260 GeV are excluded at 95% confidence level in a large part of the parameter space. For a 100 times smaller coupling strength masses up to 182 GeV are excluded.
DOI: 10.1140/epjc/s2003-01326-x
2003
Cited 17 times
Multi-electron production at high transverse momenta in ep collisions at HERA
Multi-electron production is studied at high electron transverse momentum in positron- and electron-proton collisions using the H1 detector at HERA. The data correspond to an integrated luminosity of 115 pb-1. Di-electron and tri-electron event yields are measured. Cross sections are derived in a restricted phase space region dominated by photon-photon collisions. In general good agreement is found with the Standard Model predictions. However, for electron pair invariant masses above 100 GeV, three di-electron events and three tri-electron events are observed, compared to Standard Model expectations of 0.30 \pm 0.04 and 0.23 \pm 0.04, respectively.
DOI: 10.1016/s0550-3213(01)00544-2
2001
Cited 18 times
Photoproduction with a leading proton at HERA
The total cross section for the photoproduction process with a leading proton in the final state has been measured at gamma p centre-of-mass energies W of 91, 181 and 231 GeV. The measured cross sections apply to the kinematic range with the transverse momentum of the scattered proton restricted to p_Tproton <= 0.2 GeV and 0.68 <= z <= 0.88, where z = E_p'/E_p is the scattered proton energy normalised to the beam energy. The cross section dsigma_(gamma p -> Xp')(W,z)/dz is observed to be independent of W and z within the measurement errors and amounts to 8.05 +- 0.06 stat +- 0.89 syst mub on average. The data are well described by a Triple Regge model in which the process is mediated by a mixture of exchanges with an effective Regge trajectory of intercept alpha_i(0)=0.33 +- 0.04 stat +- 0.04 syst. The total cross section for the interaction of the photon with this mixture (gamma alpha_i -> X) can be described by an effective trajectory of intercept alpha_k(0)=0.99 +- 0.01 stat +- 0.05 syst. Predictions based on previous triple Regge analyses of pp-> pX data assuming vertex factorisation are broadly consistent with the gamma p data. The measured cross sections are compared with deep inelastic scattering leading proton data in the same region of z and pT_proton for photon virtuality Q^2 > 2.5 GeV^2. The ratio of the cross section for leading proton production to the total cross section is found to rise with Q^2.
DOI: 10.1016/s0370-2693(01)01262-x
2001
Cited 18 times
A search for leptoquark bosons in e−p collisions at HERA
A search for scalar and vector leptoquarks coupling to first generation fermions is performed in the H1 experiment at the ep collider HERA. The analysis uses e−p data collected in 1998 and 1999 at a centre-of-mass energy of 320 GeV, corresponding to an integrated luminosity of ∼15 pb−1. No evidence for the direct production of such particles is found in a data sample with a large transverse momentum final state electron or with large missing transverse momentum, and constraints on leptoquark models are established. For a Yukawa coupling of electromagnetic strength leptoquarks are excluded for masses up to ∼290 GeV. This analysis complements the leptoquark searches performed previously using data collected whilst HERA was operating with positrons instead of electrons.
DOI: 10.1016/s0370-2693(02)02764-8
2002
Cited 16 times
Search for excited electrons at HERA
A search for excited electron (e∗) production is described in which the electroweak decays e∗→eγ, e∗→eZ and e∗→νW are considered. The data used correspond to an integrated luminosity of 120 pb−1 taken in e±p collisions from 1994 to 2000 with the H1 detector at HERA at centre-of-mass energies of 300 and 318 GeV. No evidence for a signal is found. Mass dependent exclusion limits are derived for the ratio of the couplings to the compositeness scale, f/Λ. These limits extend the excluded region to higher masses than has been possible in previous direct searches for excited electrons.
DOI: 10.1159/000288994
1995
Cited 16 times
To Control or to Be Controlled?
We postulated that patients with an internal locus of control, i.e. those who like to control their health problems themselves, would adapt more adequately to the 'patient-controlled analgesia' technique as compared to patients with an external health locus of control, who do not believe in their own control. Since contradicting studies have been published on this matter, we investigated relations between the demand for analgesics, perceived pain in the postoperative phase, and the health locus of control in the postoperative context of cardiac surgery. Findings demonstrate distinct utilization patterns between subjects with internal or external locus of control concerning total morphine consumption, number of unsatisfied demands and reduction of perceived pain.
DOI: 10.1016/s0370-2693(01)01155-8
2001
Cited 15 times
D∗± meson production in deep-inelastic diffractive interactions at HERA
A measurement is presented of the cross section for D∗± meson production in diffractive deep-inelastic scattering for the first time at HERA. The cross section is given for the process ep→eXY, where the system X contains at least one D∗± meson and is separated by a large rapidity gap from a low mass proton remnant system Y. The cross section is presented in the diffractive deep-inelastic region defined by 2<Q2<100 GeV2, 0.05<y<0.7, xP<0.04, MY<1.6 GeV and |t|<1 GeV2. The D∗± mesons are restricted to the range pT,D∗>2 GeV and |ηD∗|<1.5. The cross section is found to be 246±54±56 pb and forms about 6% of the corresponding inclusive D∗± cross section. The cross section is presented as a function of various kinematic variables, including zPobs which is an estimate of the fraction of the momentum of the diffractive exchange carried by the parton entering the hard-subprocess. The data show a large component of the cross section at low zPobs where the contribution of the boson–gluon-fusion process is expected to dominate. The data are compared with several QCD-based calculations.
DOI: 10.1016/s0370-2693(01)01410-1
2002
Cited 14 times
Search for excited neutrinos at HERA
We present a search for excited neutrinos using e−p data taken by the H1 experiment at HERA at a center-of-mass energy of 318 GeV with an integrated luminosity of 15 pb−1. No evidence for excited neutrino production is found. Mass dependent exclusion limits are determined for the ratio of the coupling to the compositeness scale, f/Λ, independently of the relative couplings to the SU(2) and U(1) gauge bosons. These limits extend the excluded region to higher masses than has been possible in previous searches at other colliders.
DOI: 10.1140/epjcd/s2005-02-002-4
2005
Cited 8 times
Search with the CMS detector for Randall-Sundrum excitations of gravitons decaying into electron pairs
The sensitivity of the CMS experiment to the resonant production of massive Kaluza-Klein excitations of gravitons, expected in the framework of the Randall-Sundrum model, is studied. Full simulation and reconstruction are used to investigate this production followed by graviton decay to an ${\rm e^ + e^-}$ pair. For a Randall-Sundrum model with coupling parameter c = 0.01, the graviton excitations have weak couplings to Standard Model particles. For an integrated luminosity of 100 fb-1, resonances can be discovered at the $5\sigma$ level for masses up to 1.8 TeV/c 2. Heavier resonances are accessible for larger values of the c parameter, with a mass reach of 3.8 TeV/c 2 for c = 0.1.
DOI: 10.1007/jhep02(2016)122
2016
Cited 4 times
Search for W′ → tb in proton-proton collisions at s = 8 $$ \sqrt{s}=8 $$ TeV
A search is performed for the production of a massive W′ boson decaying to a top and a bottom quark. The data analysed correspond to an integrated luminosity of 19.7 fb−1 collected with the CMS detector at the LHC in proton-proton collisions at $$ \sqrt{s}=8 $$ TeV. The hadronic decay products of the top quark with high Lorentz boost from the W′ boson decay are detected as a single top flavoured jet. The use of jet substructure algorithms allows the top quark jet to be distinguished from standard model QCD background. Limits on the production cross section of a right-handed W′ boson are obtained, together with constraints on the left-handed and right-handed couplings of the W′ boson to quarks. The production of a right-handed W′ boson with a mass below 2.02 TeV decaying to a hadronic final state is excluded at 95% confidence level. This mass limit increases to 2.15 TeV when both hadronic and leptonic decays are considered, and is the most stringent lower mass limit to date in the tb decay mode.
DOI: 10.5170/cern-2004-010.248
2005
Cited 7 times
Tests of the Boards Generating the CMS ECAL Trigger Primitives : from the On-Detector Electronics to the Off-Detector Electronics System
The trigger architecture of the CMS electromagnetic calorimeter is physically organized in two sub-systems: the On-Detector front-end electronics and the Off-Detector electronics sub-system located in the electronics cavern. The trigger primitives of the electromagnetic Level-1 trigger are partially generated by the Front-End boards and completed by the Trigger Concentrator Card belonging to the Off-detector sub-system. Both boards will be produced and tested in 2004 and 2005 for the barrel. This paper puts emphasis on the testing procedure applied to the two boards.
DOI: 10.1088/1748-0221/18/04/p04001
2023
Test beam performance of a CBC3-based mini-module for the Phase-2 CMS Outer Tracker before and after neutron irradiation
Abstract The Large Hadron Collider (LHC) at CERN will undergo major upgrades to increase the instantaneous luminosity up to 5–7.5×10 34 cm -2 s -1 . This High Luminosity upgrade of the LHC (HL-LHC) will deliver a total of 3000–4000 fb -1 of proton-proton collisions at a center-of-mass energy of 13–14 TeV. To cope with these challenging environmental conditions, the strip tracker of the CMS experiment will be upgraded using modules with two closely-spaced silicon sensors to provide information to include tracking in the Level-1 trigger selection. This paper describes the performance, in a test beam experiment, of the first prototype module based on the final version of the CMS Binary Chip front-end ASIC before and after the module was irradiated with neutrons. Results demonstrate that the prototype module satisfies the requirements, providing efficient tracking information, after being irradiated with a total fluence comparable to the one expected through the lifetime of the experiment.
DOI: 10.1016/j.annonc.2023.09.809
2023
1612P Demonstrating the complexity of need and the effectiveness of integrated palliative care: An analysis of routinely collected patient centred outcome measures
Patient centred outcome measures (PCOMs) are increasingly used to structure proactive symptom assessment and help centre care around the specific needs of the patient. This study aimed to review the use of PCOMs as part of the routine care of inpatients reviewed by the integrated palliative care team in a specialist cancer centre. Anonymised electronic palliative care PCOM data were retrieved for inpatients between 7/4/2021 to 31/01/2023, including Integrated Palliative Outcome Scale (IPOS), ECOG performance status, Australian Karnofsky Performance Status (AKPS) and Phase of Illness (POI). Descriptive statistics were used to define the complexity of palliative care needs based on IPOS, PS and POI. The effectiveness of the integrated palliative care service was evaluated by examining the difference between PCOM at initial and follow up assessment. Digital PCOM records for 1115 episodes of inpatient care were included, of which 391 had follow up data. On initial assessment 63% (703) patients had ECOG PS of 3 or 4 and 77% (864) had AKPS of less than 70. The most prevalent physical symptoms were weakness (84%, 1265), pain (80.7%, 1215), and poor mobility (72.3%, 1089). The most prevalent psychosocial symptom was family or friends feeling anxious or worried (85.8%, 1292). 83% (1250) had at least one palliative care need of severe or overwhelming intensity on initial assessment. 67.5% (753) were in an unstable POI on initial assessment, requiring urgent input. On follow up 92% (328) patients were in a stable, deteriorating or dying POI with no change to the care plan required. In patients with initial moderate to overwhelming symptoms, pain improved in 74%, nausea improved in 84%, vomiting improved in 93%, and constipation improved in 68% at follow up. The high prevalence of physical and psychosocial symptoms demonstrates the complexity of needs and provides evidence of the requirement for integration of specialist palliative care services in cancer centres. The improvement in symptom scores between initial and follow up assessment demonstrates the effectiveness of integrated palliative care for cancer centre inpatients.
DOI: 10.1016/j.physletb.2004.08.004
2004
Cited 4 times
Measurement of the proton structure function <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"><mml:msub><mml:mi>F</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> at low <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"><mml:msup><mml:mi>Q</mml:mi><mml:mn>2</mml:mn></mml:msup></mml:math> in QED Compton scattering at HERA
The proton structure function F2(x,Q2) is measured in inelastic QED Compton scattering using data collected with the H1 detector at HERA. QED Compton events are used to access the kinematic range of very low virtualities of the exchanged photon, Q2, down to 0.5 GeV2, and Bjorken x up to ∼0.06, a region which has not been covered previously by inclusive measurements at HERA. The results are in agreement with the measurements from fixed target lepton–nucleon scattering experiments.
DOI: 10.5170/cern-2005-011.231
2005
Cited 3 times
CMS ECAL Front-End boards: the XFEST project
The Front-End (FE) boards are part of the On-detector electronics system of the CMS electromagnetic calorimeter (ECAL). Their digital functionalities and properties are tested by a dedicated test bench located at Laboratoire Leprince-Ringuet, prior to the board integration in the CMS detector at CERN. XFEST, acronym for eXtended Front-End System Test, is designed to perform tests that can last several hours, on up to 12 FE boards in parallel. The system is designed to deliver 80 tested boards per week. This contribution presents the XFEST set-up and the results of the measurements on FE boards.
2005
Cited 3 times
TeV electron and photon saturation studies
2003
Cited 3 times
Prospects for Study of Randall-Sundrum Gravitons in the CMS Experiment
DOI: 10.3917/vaca.069.0141
2014
Marxisme magique
Résumé Hantises sociales
DOI: 10.1088/1748-0221/17/06/p06039
2022
Beam test performance of a prototype module with Short Strip ASICs for the CMS HL-LHC tracker upgrade
Abstract The Short Strip ASIC (SSA) is one of the four front-end chips designed for the upgrade of the CMS Outer Tracker for the High Luminosity LHC. Together with the Macro-Pixel ASIC (MPA) it will instrument modules containing a strip and a macro-pixel sensor stacked on top of each other. The SSA provides both full readout of the strip hit information when triggered, and, together with the MPA, correlated clusters called stubs from the two sensors for use by the CMS Level-1 (L1) trigger system. Results from the first prototype module consisting of a sensor and two SSA chips are presented. The prototype module has been characterized at the Fermilab Test Beam Facility using a 120 GeV proton beam.
DOI: 10.5170/cern-2005-011.400
2005
A Real Time Electronics Emulator with Realistic Data Generation for Reception Tests of the CMS ECAL Front-End Boards
The CMS [1] electromagnetic calorimeter (ECAL) [2] uses 3 132 Front-End boards (FE) performing both trigger and data readout functions. Prior to their integration at CERN, the FE boards have to be validated by dedicated test bench systems. The final one, called “XFEST” (eXtended FrontEnd System Test) and for which the present developments have been performed, is located at Laboratoire Leprince-Ringuet. In this contribution, a solution is described to efficiently test a large set of complex electronics boards characterized by a large number of input ports and a high throughput data rate. To perform it, an algorithm to simulate the Very Front End signals has been emulated. The project firmwares use VHDL embedded into XILINX Field Programmable Gate Array circuits (FPGA). This contribution describes the solutions developed in order to create a realistic digital input patterns real-time emulator working at 40 MHz. The implementation of a real time comparison of the FE output streams as well as the test bench will be also presented.
2017
Searches for third generation squarks with CMS
Searches for the direct pair production of the third generation squarks are presented in this conference report, based on proton-proton collisions at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 35.9 fb$^{-1}$, collected by the CMS detector. New techniques have been developed to address different kinematical regimes. In absence of statistically significant deviations from the standard model background, limits have been derived in terms of simplified model spectra, excluding for example a stop up to a mass of 1.05~TeV when it decays to a top and a massless neutralino.
2006
Search with the CMS detector for heavy resonances decaying into an electron pair
DOI: 10.3204/pubdb-2017-00516
2016
Search for high-mass Z gamma resonances at sqrt(s) = 8 and 13 TeV using jet substructure techniques
A search for massive resonances decaying to a Z boson and a photon is performed in events with a hadronically decaying Z boson candidate, separately in light-quark and b quark decay modes, identified using jet substructure and advanced b tagging techniques. Results are based on samples of proton-proton collisions collected with the CMS detector at the LHC at center-of-mass energies of 8 and 13 TeV, corresponding to integrated luminosities of 19.7 and 2.7 inverse femtobarns, respectively. The results of the search are combined with those of a similar search in the leptonic decay modes of the Z boson, based on the same data sets. Spin-0 resonances with various widths and with masses in a range between 0.2 and 3.0 TeV are considered. No significant excess is observed either in the individual analyses or the combination. The results are presented in terms of upper limits on the production cross section of such resonances and constitute the most stringent limits to date for a wide range of masses.
DOI: 10.3204/desy-proc-2014-02/40
2014
Stop and other searches
DOI: 10.5167/uzh-140765
2016
Observation of Upsilon(1S) pair production in proton-proton collisions at sqrt(s) = 8 TeV
DOI: 10.1016/j.physletb.2016.063.027
2016
Measurement of the inelastic cross section in proton-lead collisions at a centre-of-mass energy per nucleon pair of 5.02 TeV
The inelastic hadronic cross section in proton-lead collisions at a centre-of-mass energy per nucleon pair of 5.02 TeV is measured with the CMS detector at the LHC. The data sample, corresponding to an integrated luminosity of 12.6 +/- 0.4 inverse nanobarns, has been collected with an unbiased trigger for inclusive particle production. The cross section is obtained from the measured number of proton-lead collisions with hadronic activity produced in the pseudorapidity ranges 3<abs(eta)<5 and/or -5<abs(eta)<-3, corrected for photon-induced contributions, experimental acceptance, and other instrumental effects. The inelastic cross section is measured to be sigma[inel,pPb]=2061 +/- 3 (stat) +/- 34 (syst) +/- 72 (lum) mb. Various Monte Carlo generators, commonly used in heavy ion and cosmic ray physics, are found to reproduce the data within uncertainties. The value of sigma[inel,pPb] is compatible with that expected from the proton-proton cross section at 5.02 TeV scaled up within a simple Glauber approach to account for multiple scatterings in the lead nucleus, indicating that further net nuclear corrections are small.
DOI: 10.1017/s007542690010936x
1973
JHS volume 93 Cover and Front matter
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DOI: 10.1016/j.nima.2010.02.210
2010
Electronic calibration of the ATLAS LAr calorimeter
The Liquid Argon (LAr) calorimeter is a key detector component in the ATLAS experiment at the LHC, designed to provide precision measurements of electrons, photons, jets and missing transverse energy.A critical element in the precision measurement is the electronic calibration.In this article, the computation of the energy deposited in a cell is presented as well as the role of the different calibration constants, revealing the complex calibration scheme which has been put in place.Since the installation of the LAr calorimeter in the ATLAS cavern, the electronic calibration of the readout system has been continuously exercised in the commissioning phase.The large amount of collected calibration data allows careful studies of the stability of constants, like pedestals and pulse shapes.Thanks to the experience gained during the last two years, a calibration procedure has been put in place for the LHC running period.
2017
Searches for third generation squarks with CMS : arXiv
2017
Measurement of the ttbar production cross section using events with one lepton and at least one jet in pp collisions at sqrt(s)=13 TeV
A measurement of the ttbar production cross section at sqrt(s)=13 TeV is presented using proton-proton collisions, corresponding to an integrated luminosity of 2.3 inverse femtobarns, collected with the CMS detector at the LHC. Final states with one isolated charged lepton (electron or muon) and at least one jet are selected and categorized according to the accompanying jet multiplicity. From a likelihood fit to the invariant mass distribution of the isolated lepton and a jet identified as coming from the hadronization of a bottom quark, the cross section is measured to be sigma(ttbar)= 835 +/- 3 (stat) +/- 23 (syst) +/- 23 (lum) pb, in agreement with the standard model prediction. Using the expected dependence of the cross section on the pole mass of the top quark (m[t]), the value of m[t] is found to be 172.7+2.4-2.7 GeV.
DOI: 10.48550/arxiv.1709.00868
2017
Searches for third generation squarks with CMS
Searches for the direct pair production of the third generation squarks are presented in this conference report, based on proton-proton collisions at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 35.9 fb$^{-1}$, collected by the CMS detector. New techniques have been developed to address different kinematical regimes. In absence of statistically significant deviations from the standard model background, limits have been derived in terms of simplified model spectra, excluding for example a stop up to a mass of 1.05~TeV when it decays to a top and a massless neutralino.
2008
Searches for the higgs boson and extra dimensions at the LHC
DOI: 10.22323/1.364.0561
2020
Searches for direct production of third generation squarks at CMS
Searches for direct pair production of the third generation squarks (the supersymmetric partners of the top and bottom quarks) are presented, based on proton-proton collision data recorded by the CMS experiment during the LHC Run2 operations (2016-2018). These searches are performed in final states with one single lepton (electron or muon), a pair of tau leptons, or zero lepton. In absence of statistically significant deviations from the standard model background, the results are interpreted in the context of several decay modes of top squarks and for one decay mode of the bottom squarks.
2019
Searches for direct production of third generation squarks at CMS
DOI: 10.1017/s0009840x00121067
1988
CAR volume 38 issue 2 Front matter
Dr Hinds gives a close reading of the two accounts of the myth of Persephone to be found in Ovid's poetry, the one in Metamorphoses 5, the other in Fasti 4. The book is at once a literary historical enquiry into the double transformation of the rape of Persephone and a critical exploration of the self-conscious delight
2006
Workshop on CP Sudies and Non-Standard Physics.
2006
Search for heavy resonances
2006
CP Studies and Non-Standard Higgs Physics
There are many possibilities for new physics beyond the Standard Model that feature non-standard Higgs sectors. These may introduce new sources of CP violation, and there may be mixing between multiple Higgs bosons or other new scalar bosons. Alternatively, the Higgs may be a composite state, or there may even be no Higgs at all. These non-standard Higgs scenarios have important implications for collider physics as well as for cosmology, and understanding their phenomenology is essential for a full comprehension of electroweak symmetry breaking. This report discusses the most relevant theories which go beyond the Standard Model and its minimal, CP-conserving supersymmetric extension: two-Higgs-doublet models and minimal supersymmetric models with CP violation, supersymmetric models with an extra singlet, models with extra gauge groups or Higgs triplets, Little Higgs models, models in extra dimensions, and models with technicolour or other new strong dynamics. For each of these scenarios, this report presents an introduction to the phenomenology, followed by contributions on more detailed theoretical aspects and studies of possible experimental signatures at the LHC and other colliders.
2004
Physics at the Large Hadron Collider
DOI: 10.1142/9789812705136_0011
2003
DIFFRACTION AT HERA
DOI: 10.3917/criti.884.0083
2021
Fantômes historiographes
2000
Coexisting structures in the 120-124Te nuclei
2000
Helicity Structure of rho Meson Electroproduction
2002
Mesure de la structure en hélicité de la réaction e + p --> e + p + Y en fonction de t à HERA
DOI: 10.1109/plasma.2000.855086
2002
XeCl excimer fluorescence in a microwave discharge
Summary form only given. Ultraviolet light sources are becoming increasingly useful to manufacturing applications such as the curing of inks, coatings, and adhesives. Intensive ultraviolet light can provide efficient curing without intense heat. Microwave driven lamps have many advantages including long lifetime, high overall efficiencies and high intensity emission; XeCl is one of many rare-gas halide excimers used in these systems. The experiment described here is used to understand the production mechanisms of XeCl as well as the optimal conditions for ultraviolet emission. A continuous wave discharge produced by 2.45 GHz microwaves is used to produce 308 nm fluorescence (B/spl rarr/X) and 236 nm fluorescence (D/spl rarr/X). Varying ratios of Xe and Cl/sub 2/, are controlled by mass flow controllers and mixed in a mixing cell before flowing into a quartz tube, which lies along the centerline axis of an Asmussen microwave cavity. The emission of 236 nm tends to be much dimmer than the more prominent 308 nm emission. Emission from Xe atoms are also observed. Pressure ranges from a few torr to over 100 torr are used with microwave powers ranging from 100 W to 300 W. A comparison of the XeCl emission using different ratios of Xe and Cl/sub 2/, and trends in power and pressure will be presented.
DOI: 10.1142/9789812778345_0107
2002
MEASUREMENT OF DENSITY MATRIX ELEMENTS FOR ρ MESON ELECTROPRODUCTION AS A FUNCTION OF t
DOI: 10.3204/desy-thesis-2002-042
2002
Mesure de la structure en hélicité de la réaction $e + p \rightarrow e + \rho + Y$ en fonction de $t$ à HERA