Publications (295)646.35 Total impact
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ABSTRACT: A search for excited electrons is performed using the full e±p data sample collected by the H1 experiment at HERA, corresponding to a total luminosity of 475 pb−1. The electroweak decays of excited electrons e∗→eγ, e∗→eZ and e∗→νW with subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for excited electron production is found. Mass dependent exclusion limits on e∗ production cross sections and on the ratio f/Λ of the coupling to the compositeness scale are derived within gauge mediated models. These limits extend the excluded region compared to previous excited electron searches. The e∗ production via contact interactions is also addressed for the first time in ep collisions.Physics Letters B 09/2013; 666(2):131139. · 4.57 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Deepinelastic e^\pm p scattering at high squared momentum transfer Q^2 up to 30000 GeV^2 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 d sigma / d Q^2, 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 Lambda ranging between 1.6  5.5 TeV. Couplings and masses of leptoquarks and squarks in Rparity violating supersymmetry are constrained to M / lambda > 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 M_S > 0.8 TeV. A form factor analysis yields a bound on the radius of light quarks of R_q < 1.0 x 10^18 m.Physics Letters B 09/2013; 568:3547. · 4.57 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: 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 117 pb−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 275–325 GeV are ruled out at 95% confidence level. These limits improve and supercede earlier H1 limits based on subsamples of the data used here.Physics Letters B 09/2013; 629(1):919. · 4.57 Impact Factor 
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ABSTRACT: Cross sections for elastic and protondissociative photoproduction of J/psi mesons are measured with the H1 detector in positronproton collisions at HERA. The data were collected at $ep$ centreofmass energies sqrt{s} approx 318 GeV and sqrt{s} approx 225 GeV, corresponding to integrated luminosities of L = 130 pb^{1} and L = 10.8 pb^{1}, respectively. The cross sections are measured as a function of the photonproton centreofmass energy in the range 25< Wgp < 110 GeV. Differential cross sections $\mathrm{d}\sigma / \mathrm{d}t$, where $t$ is the squared fourmomentum transfer at the proton vertex, are measured in the range $t < 1.2 \, \gevsq$ for the elastic process and $t < 8 \, \gevsq$ for proton dissociation. The results are compared to other measurements. The $\Wgp$ and $t$dependences are parametrised using phenomenological fits.European Physical Journal C 04/2013; 73:2466. · 5.25 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Charged particle production in deepinelastic ep scattering is measured with the H1 detector at HERA. The kinematic range of the analysis covers low photon virtualities, 5 < Q^2 < 100 GeV^2, and small values of Bjorkenx, 10^{4} < x < 10^{2}. The analysis is performed in the hadronic centreofmass system. The charged particle densities are measured as a function of pseudorapidity (eta^*) and transverse momentum (p_T^*) in the range 0< \eta^* < 5 and 0< p_T^* < 10$ GeV differentially in x and Q^2. The data are compared to predictions from different Monte Carlo generators implementing various options for hadronisation and parton evolutions.European Physical Journal C 02/2013; 73:2406. · 5.25 Impact Factor 
Dataset: desy06110

Dataset: desy06110
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ABSTRACT: Measurements of open charm production cross sections in deepinelastic ep scattering at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross sections sigma_red^{c\bar{c}} for charm production are obtained in the kinematic range of photon virtuality 2.5<Q2<2000 GeV2 and Bjorken scaling variable 0.00003<x<0.05. The combination method accounts for the correlations of the systematic uncertainties among the different data sets. The combined charm data together with the combined inclusive deepinelastic scattering cross sections from HERA are used as input for a detailed NLO QCD analysis to study the influence of different heavy flavour schemes on the parton distribution functions. The optimal values of the charm mass as a parameter in these different schemes are obtained. The implications on the NLO predictions for W^{\pm} and Z production cross sections at the LHC are investigated. Using the fixed flavour number scheme, the running mass of the charm quark is determined.European Physical Journal C 01/2013; 73:2311. · 5.25 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centreofmass energy sqrt(s) = 318 GeV where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6% for the most precise points. The combined data cover the range 2.5 < Q2 < 200 GeV2 in photon virtuality, 0.00035 < xIP < 0.09 in proton fractional momentum loss, 0.09 < t < 0.55 GeV2 in squared fourmomentum transfer at the proton vertex and 0.0018 < beta < 0.816 in beta = x/xIP, where x is the Bjorken scaling variable.European Physical Journal C 07/2012; 72:2175. · 5.25 Impact Factor 
Article: Inclusive Deep Inelastic Scattering at High Q2 with LongitudinallyPolarised Lepton Beams at HERA
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ABSTRACT: Inclusive e\pmp 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 centreofmass energy of \surds = 319GeV with a total integrated luminosity of 333.7 pb1 shared between two lepton beam charges and two longitudinal lepton polarisation modes. The differential cross sections are measured in the range of negative fourmomentum transfer squared, Q2, between 60 and 50 000GeV2, 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^gammaZ. A measurement of the neutral current parity violating structure function F_2^gammaZ 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 nexttoleading order QCD fit based on all published H1 inclusive cross section data which are used to extract the parton distribution functions of the proton.Journal of High Energy Physics 06/2012; 1209:061. · 5.62 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: The cross section for ep > e b\bar{b} X in photoproduction is measured with the H1 detector at the epcollider HERA. The decay channel b\bar{b} > ee X' is selected by identifying the semielectronic decays of the bquarks. The total production cross section is measured in the kinematic range given by the photon virtuality Q^2 <= 1 GeV^2, the inelasticity 0.05 <= y <= 0.65 and the pseudorapidity of the bquarks eta(b),eta(\bar{b}) <= 2. The differential production cross section is measured as a function of the average transverse momentum of the beauty quarks <P_T(b)> down to the threshold. The results are compared to nexttoleadingorder QCD predictions.European Physical Journal C 06/2012; · 5.25 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: A measurement of the integrated luminosity at the ep collider HERA is presented, exploiting the elastic QED Compton process ep \rightarrow ep. The electron and the photon are detected in the backward calorimeter of the H1 experiment. The integrated luminosity of the data recorded in 2003 to 2007 is determined with a precision of 2.3%. The measurement is found to be compatible with the corresponding result obtained using the BetheHeitler process.European Physical Journal C 05/2012; 72(10). · 5.25 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: First measurements are presented of the diffractive cross section $\sigma_{ep \rightarrow eXY}$ at centreofmass energies $\sqrt{s}$ of 225 and 252 GeV, together with a precise new measurement at $\sqrt{s}$ of 319 GeV, using data taken with the H1 detector in the years 2006 and 2007. Together with previous H1 data at $\sqrt{s}$ of 301 GeV, the measurements are used to extract the diffractive longitudinal structure function F_L^D in the range of photon virtualities 4.0 <= Q^2 <= 44.0 GeV^2 and fractional proton longitudinal momentum loss 5 10^{4} <= x_{IP} <= 3 10^{3}. The measured F_L^D is compared with leading twist predictions based on diffractive parton densities extracted in NLO QCD fits to previous measurements of diffractive DeepInelastic Scattering and with a model which additionally includes a higher twist contribution derived from a colour dipole approach. The ratio of the diffractive cross section induced by longitudinally polarised photons to that for transversely polarised photons is extracted and compared with the analogous quantity for inclusive DeepInelastic Scattering.European Physical Journal C 07/2011; · 5.25 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: The cross section for the diffractive deepinelastic scattering process ep→eXp is measured, with the leading final state proton detected in the H1 Forward Proton Spectrometer. The data sample covers the range x ℙ<0.1 in fractional proton longitudinal momentum loss, 0.1<t<0.7 GeV2 in squared fourmomentum transfer at the proton vertex and 4European Physical Journal C 01/2011; 71:1578. · 5.25 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Measurements of cross sections for events with charm and beauty jets in deep inelastic scattering at HERA are presented. Events with jets of transverse energy GeV and pseudorapidity −1.0<η jet<1.5 in the laboratory frame are selected in the kinematic region of photon virtuality Q 2>6 GeV2 and inelasticity variable 0.07European Physical Journal C. 01/2011;  [Show abstract] [Hide abstract]
ABSTRACT: A search for second and third generation scalar and vector leptoquarks produced in ep collisions via the lepton flavour violating processes ep > mu X and ep > tau X is performed by the H1 experiment at HERA. The full data sample taken at a centreofmass energy sqrt{s} = 319 GeV is used for the analysis, corresponding to an integrated luminosity of 245 pb^1 of e^+ p and 166 pb^1 of e^ p collision data. No evidence for the production of such leptoquarks is observed in the H1 data. Leptoquarks produced in e^+ p collisions with a coupling strength of lambda=0.3 and decaying with the same coupling strength to a muonquark pair or a tauquark pair are excluded at 95% confidence level up to leptoquark masses of 712 GeV and 479 GeV, respectively.01/2011;  [Show abstract] [Hide abstract]
ABSTRACT: 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 460GeV. The kinematic range of the measurement covers low absolute fourmomentum transfers squared, 1.5GeV2<Q 2<120GeV2, 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 =920GeV and E p =820GeV. The new measurements are used to test several phenomenological and QCD models applicable in this low Q 2 and low x kinematic domain.European Physical Journal C 01/2011; 71(3):150. · 5.25 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: A search for squarks in Rparity violating supersymmetry is performed in e ± p collisions at HERA using the H1 detector. The full data sample taken at a centreofmass energy Ös=319\sqrt{s}=319GeV is used for the analysis, corresponding to an integrated luminosity of 255pb−1 of e + p and 183pb−1 of e − p collision data. The resonant production of squarks via a Yukawa coupling λ′ is considered, taking into account direct and indirect Rparity violating decay modes. Final states with jets and leptons are investigated. No evidence for squark production is found and mass dependent limits on λ′ are obtained in the framework of the Minimal Supersymmetric Standard Model and in the Minimal Supergravity Model. In the considered part of the parameter space, for a Yukawa coupling of electromagnetic strength λ′=0.3, squarks of all flavours are excluded up to masses of 275GeV at 95% confidence level, with downtype squarks further excluded up to masses of 290GeV.European Physical Journal C 01/2011; 71(3):116. · 5.25 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: A search for first generation scalar and vector leptoquarks produced in ep collisions is performed by the H1 Collaboration at HERA. The full H1 data sample is used in the analysis, corresponding to an integrated luminosity 446 pb^1. No evidence for the production of leptoquarks is observed in final states with a large transverse momentum electron or with large missing transverse momentum, and constraints on leptoquark models are derived. For leptoquark couplings of electromagnetic strength lambda=0.3, first generation leptoquarks with masses up to 800 GeV are excluded at 95% confidence level.Physics Letters B 01/2011; 704:388396. · 4.57 Impact Factor
Publication Stats
430  Citations  
646.35  Total Impact Points  
Top Journals
Institutions

1999–2013

Joint Institute for Nuclear Research
Dubno, Moskovskaya, Russia


2010–2011

University of Antwerp
Antwerpen, Flanders, Belgium


2006–2007

Comenius University in Bratislava
Presburg, Bratislavský, Slovakia


2003–2005

University of Birmingham
 School of Physics and Astronomy
Birmingham, ENG, United Kingdom
