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 diffractiveψ(2S) cross section is found to be similar to or possibly somewhat s teeper than that for J/ψ mesons. The dependences of the elastic and proton dissociat ive ψ(2S) photoproduction cross sections on the squared momentum tra nsfe t at the proton vertex are measured. The t-dependence of the elastic channel, parametrised as ebt, yields b ψ(2S) el = (4.31 ± 0.57 ± 0.46) GeV −2, compatible with that of theJ/ψ. For the proton dissociative channel the result b pd = (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 perturbat ive QCD are found to describe the measurements well. To be submitted to Phys. Lett. B C. Adloff, V. Andreev, B. Andrieu, T. Anthonis, A. Astvatsatourov , A. Babaev, J. Bähr, P. Baranov , E. Barrelet , W. Bartel, S. Baumgartner , J. Becker , M. Beckingham, A. Beglarian, O. Behnke, C. Beier, A. Belousov, Ch. Berger , T. Berndt, J.C. Bizot , J. Böhme, V. Boudry, W. Braunschweig , V. Brisson, H.-B. Bröker, D.P. Brown, W. Brückner , D. Bruncko, F.W. Büsser , A. Bunyatyan, A. Burrage, G. Buschhorn , L. Bystritskaya, A.J. Campbell , S. Caron, F. Cassol-Brunner , D. Clarke, C. Collard, J.G. Contreras , Y.R. Coppens , J.A. Coughlan, M.-C. Cousinou, B.E. Cox, G. Cozzika, J. Cvach, J.B. Dainton, W.D. Dau, K. Daum, M. Davidsson, B. Delcourt, N. Delerue, R. Demirchyan, A. De Roeck, E.A. De Wolf, C. Diaconu, J. Dingfelder , P. Dixon, V. Dodonov, J.D. Dowell, A. Droutskoi, A. Dubak, C. Duprel , G. Eckerlin, D. Eckstein, V. Efremenko, S. Egli, R. Eichler, F. Eisele, E. Eisenhandler , M. Ellerbrock, E. Elsen, M. Erdmann, W. Erdmann, P.J.W. Faulkner , L. Favart, A. Fedotov, R. Felst , J. Ferencei , S. Ferron, M. Fleischer , P. Fleischmann , Y.H. Fleming, G. Flügge, A. Fomenko, I. Foresti , J. Formánek , G. Franke, G. Frising, E. Gabathuler , K. Gabathuler , J. Garvey, J. Gassner , J. Gayler , R. Gerhards , C. Gerlich, S. Ghazaryan , L. Goerlich, N. Gogitidze, C. Grab, V. Grabski , H. Grässler , T. Greenshaw, G. Grindhammer , T. Hadig, D. Haidt, L. Hajduk, J. Haller, W.J. Haynes , B. Heinemann , G. Heinzelmann , R.C.W. Henderson , S. Hengstmann , H. Henschel , R. Heremans , G. Herrera, I. Herynek, M. Hildebrandt , M. Hilgers, K.H. Hiller, J. Hladký, P. Höting, D. Hoffmann, R. Horisberger , A. Hovhannisyan , S. Hurling, M. Ibbotson, Ç. İşsever , M. Jacquet , M. Jaffre, L. Janauschek , X. Janssen , V. Jemanov , L. Jönsson , C. Johnson , D.P. Johnson , M.A.S. Jones , H. Jung, D. Kant, M. Kapichine, M. Karlsson, O. Karschnick, F. Keil, N. Keller, J. Kennedy , I.R. Kenyon, S. Kermiche, C. Kiesling, P. Kjellberg, M. Klein, C. Kleinwort, T. Kluge, G. Knies, B. Koblitz, S.D. Kolya, V. Korbel, P. Kostka, S.K. Kotelnikov, R. Koutouev, A. Koutov, J. Kroseberg , K. Krüger, T. Kuhr, T. Kurča, D. Lamb, M.P.J. Landon , W. Lange, T. Laštovička, P. Laycock, E. Lebailly, A. Lebedev, B. Leißner , R. Lemrani , V. Lendermann, S. Levonian, M. Lindstroem, B. List, E. Lobodzinska , B. Lobodzinski , A. Loginov, N. Loktionova, V. Lubimov, S. Lüders, D. Lüke, L. Lytkin, N. Malden, E. Malinovski, I. Malinovski, S. Mangano , R. Maraček, P. Marage, J. Marks, R. Marshall , H.-U. Martyn, J. Martyniak, S.J. Maxfield, D. Meer, A. Mehta, K. Meier, A.B. Meyer, H. Meyer, J. Meyer , P.-O. Meyer , S. Mikocki, D. Milstead, S. Mohrdieck, M.N. Mondragon, F. Moreau, A. Morozov, J.V. Morris, K. Müller, P. Murı́n, V. Nagovizin, B. Naroska, J. Naumann , Th. Naumann, G. Nellen, P.R. Newman , F. Niebergall , C. Niebuhr , O. Nix, G. Nowak, J.E. Olsson , D. Ozerov, V. Panassik , C. Pascaud , G.D. Patel , M. Peez, E. Perez, A. Petrukhin, J.P. Phillips, D. Pitzl, R. Pöschl , I. Potachnikova , B. Povh, G. Rädel , J. Rauschenberger , P. Reimer , B. Reisert , C. Risler, E. Rizvi, P. Robmann , R. Roosen, A. Rostovtsev , S. Rusakov , K. Rybicki, J. Samson , D.P.C. Sankey , S. Schätzel , J. Scheins , F.-P. Schilling, P. Schleper , D. Schmidt , D. Schmidt , S. Schmidt , S. Schmitt , M. Schneider , L. Schoeffel , A. Schöning, T. Schörner , V. Schröder , H.-C. Schultz-Coulon , C. Schwanenberger , K. Sedlák, F. Sefkow, V. Shekelyan, I. Sheviakov, L.N. Shtarkov, Y. Sirois, T. Sloan, P. Smirnov, Y. Soloviev, D. South, V. Spaskov, A. Specka, H. Spitzer , R. Stamen,

The helicity structure of the diffractive electroproducti on of mesons, e+ p ! e+ + Y , is studied in a previously unexplored region of large four-m omentum transfer squared at the proton vertex,t: 0 < t < 3 G eV , wheret = jtj jtjm in . The data used are collected with the H1 detector at HERA in the kinematic domai n 2:5 < Q 2 < 60 G eV , 40 < W < 120 GeV. Notdependence of the r 00 spin density matrix element is found. A significanttdependent helicity non-conservation from the virtual phot on to the meson is observed for the spin density matrix element combination s r 00 + 2r 11 andr 00 + 2r 11 . Thesetdependences are consistently described by a perturbative Q CD model based on the exchange of two gluons. C. Adloff, V. Andreev, B. Andrieu, T. Anthonis, V. Arkadov, A. Astvatsatourov , A. Babaev, J. Bähr , P. Baranov , E. Barrelet , W. Bartel, J. Becker , A. Beglarian, O. Behnke, C. Beier, A. Belousov, Ch. Berger , T. Berndt, J.C. Bizot , J. Böhme, V. Boudry, W. Braunschweig , V. Brisson, H.-B. Bröker, D.P. Brown, W. Brückner , D. Bruncko, J. Bürger , F.W. Büsser , A. Bunyatyan, A. Burrage, G. Buschhorn , L. Bystritskaya, A.J. Campbell , J. Cao, S. Caron, F. Cassol-Brunner , D. Clarke, B. Clerbaux, C. Collard, J.G. Contreras , Y.R. Coppens , J.A. Coughlan, M.-C. Cousinou, B.E. Cox, G. Cozzika, J. Cvach, J.B. Dainton, W.D. Dau, K. Daum, M. Davidsson, B. Delcourt, N. Delerue, R. Demirchyan, A. De Roeck, E.A. De Wolf, C. Diaconu, J. Dingfelder , P. Dixon, V. Dodonov, J.D. Dowell, A. Droutskoi, A. Dubak, C. Duprel , G. Eckerlin, D. Eckstein, V. Efremenko, S. Egli, R. Eichler, F. Eisele, E. Eisenhandler , M. Ellerbrock, E. Elsen, M. Erdmann, W. Erdmann, P.J.W. Faulkner , L. Favart, A. Fedotov, R. Felst , J. Ferencei , S. Ferron, M. Fleischer , Y.H. Fleming, G. Flügge, A. Fomenko, I. Foresti , J. Formánek , G. Franke, E. Gabathuler , K. Gabathuler , J. Garvey, J. Gassner , J. Gayler , R. Gerhards , C. Gerlich, S. Ghazaryan , L. Goerlich, N. Gogitidze, C. Grab, V. Grabski , H. Grässler , T. Greenshaw, G. Grindhammer , T. Hadig, D. Haidt, L. Hajduk, J. Haller, W.J. Haynes , B. Heinemann, G. Heinzelmann , R.C.W. Henderson , S. Hengstmann , H. Henschel , R. Heremans , G. Herrera, I. Herynek, M. Hildebrandt , M. Hilgers, K.H. Hiller, J. Hladký, P. Höting, D. Hoffmann, R. Horisberger , A. Hovhannisyan , S. Hurling, M. Ibbotson, Ç. İşsever , M. Jacquet , M. Jaffre, L. Janauschek , X. Janssen , V. Jemanov, L. Jönsson , C. Johnson , D.P. Johnson , M.A.S. Jones , H. Jung, D. Kant, M. Kapichine, M. Karlsson, O. Karschnick, F. Keil, N. Keller, J. Kennedy, I.R. Kenyon, S. Kermiche, C. Kiesling, P. Kjellberg, M. Klein, C. Kleinwort, T. Kluge, G. Knies, B. Koblitz, S.D. Kolya, V. Korbel, P. Kostka, S.K. Kotelnikov, R. Koutouev, A. Koutov, H. Krehbiel , J. Kroseberg , K. Krüger, A. Küpper, T. Kuhr, T. Kurča, D. Lamb, M.P.J. Landon , W. Lange, T. Laštovička, P. Laycock, E. Lebailly, A. Lebedev, B. Leißner , R. Lemrani , V. Lendermann, S. Levonian, M. Lindstroem, B. List, E. Lobodzinska , B. Lobodzinski , A. Loginov, N. Loktionova, V. Lubimov, S. Lüders, D. Lüke, L. Lytkin, H. Mahlke-Krüger , N. Malden, E. Malinovski, I. Malinovski, R. Maraček, P. Marage, J. Marks, R. Marshall , H.-U. Martyn, J. Martyniak, S.J. Maxfield, D. Meer, A. Mehta, K. Meier, A.B. Meyer, H. Meyer, J. Meyer , P.-O. Meyer , S. Mikocki, D. Milstead, T. Mkrtchyan, R. Mohr, S. Mohrdieck, M.N. Mondragon, F. Moreau, A. Morozov, J.V. Morris, K. Müller, P. Murı́n, V. Nagovizin, B. Naroska, J. Naumann , Th. Naumann , G. Nellen, P.R. Newman , F. Niebergall , C. Niebuhr , O. Nix, G. Nowak, J.E. Olsson , D. Ozerov, V. Panassik , C. Pascaud , G.D. Patel , M. Peez, E. Perez , J.P. Phillips, D. Pitzl, R. Pöschl , I. Potachnikova, B. Povh, G. Rädel , J. Rauschenberger , P. Reimer , B. Reisert , D. Reyna, C. Risler, E. Rizvi, P. Robmann , R. Roosen, A. Rostovtsev , S. Rusakov , K. Rybicki, D.P.C. Sankey , S. Schätzel , J. Scheins , F.-P. Schilling, P. Schleper , D. Schmidt , D. Schmidt , S. Schmidt , S. Schmitt , M. Schneider , L. Schoeffel , A. Schöning, T. Schörner , V. Schröder , H.-C. Schultz-Coulon , C. Schwanenberger , K. Sedlák, F. Sefkow, V. Shekelyan, I. Sheviakov, L.N. Shtarkov, Y. Sirois, T. Sloan, P. Smirnov, Y. Soloviev, D. South, V. Spaskov, A. Specka, H. Spitzer ,

The DAQ/HLT system of the ATLAS experiment at CERN, Switzerland, is being commissioned for first collisions in 2009. Presently, the system is composed of an already very large farm of computers that accounts for about one-third of its final event processing capacity. Event selection is conducted in two steps after the hardware-based Level-1 Trigger: a Level-2 Trigger processes detector data based on regions of interest (RoI) and an Event Filter operates on the full event data assembled by the Event Building system. The detector read out is fully commissioned and can be operated at its full design capacity. This places the responsibility on the High-Level Triggers system to select only events of highest physics interest that will finally reach the offline reconstruction farms. This paper brings an overview of the current ATLAS DAQ/HLT implementation and performance based on studies originated from its operation with simulated, cosmic particles and first-beam data. Its built-in event processing parallelism is presented and discussed.

The High Level Trigger (HLT) of the ATLAS experiment at the Large Hadron Collider receives events which pass the LVL1 trigger at ∼75 kHz and has to reduce the rate to ∼200 Hz while retaining the most interesting physics. It is a software trigger and performs the reduction in two stages: the LVL2 trigger and the Event Filter (EF). At the heart of the HLT is the Steering software. To minimise processing time and data transfers it implements the novel event selection strategies of seeded, step-wise reconstruction and early rejection. The HLT is seeded by regions of interest identified at LVL1. These and the static configuration determine which algorithms are run to reconstruct event data and test the validity of trigger signatures. The decision to reject the event or continue is based on the valid signatures, taking into account pre-scale and pass-through. After the EF, event classification tags are assigned for streaming purposes. Several new features for commissioning and operation have been added: comprehensive monitoring is now built in to the framework; for validation and debugging, reconstructed data can be written out; the steering is integrated with the new configuration (presented separately), and topological and global triggers have been added. This paper will present details of the final design and its implementation, the principles behind it, and the requirements and constraints it is subject to. The experience gained from technical runs with realistic trigger menus will be described.

The ATLAS experiment at the Large Hadron Collider (LHC) will face the challenge of efficiently selecting interesting candidate events in pp collisions at 14 TeV centre-of-mass energy, whilst rejecting the enormous number of background events. The High-Level-Trigger (HLT second level trigger and Event Filter), which is a software based trigger will need to reduce the first level trigger output rate of kHz to Hz written out to mass storage. In this paper an overview of the steering mechanism of the HLT is given. The HLT Steering is responsible for the scheduling of algorithms and for the global event trigger decision evaluation. The concept of step-wise and seeded selection strategy implemented by the steering will be presented. Integration of large number of trigger menus and sophisticated physics selection strategies will also be discussed. The electron and photon menus will be described to demonstrate that the trigger is well adapted for the physics program at the LHC.

The ATLAS experiment under construction at CERN is due to begin operation at the end of 2007. The detector will record the results of proton-proton collisions at a center-of-mass energy of 14 TeV. The trigger is a three-tier system designed to identify in real-time potentially interesting events that are then saved for detailed offline analysis. The trigger system will select approximately 200 Hz of potentially interesting events out of the 40 MHz bunch-crossing rate (with 109 interactions per second at the nominal luminosity).

Three- and four-jet production is measured in deep-inelastic ep scattering at low x and Q 2 with the H1 detector using an integrated luminosity of 44.2 pb -1 . Several phase space regions are selected for the three-jet analysis in order to study the underlying parton dynamics from global topologies to the more restrictive regions of forward jets close to the proton direction. The measurements of cross sections for events with at least three jets are compared to fixed order QCD predictions of 𝒪(α_s^2) and 𝒪(α_s^3) and with Monte Carlo simulation programs where higher order effects are approximated by parton showers. A good overall description is provided by the 𝒪(α_s^3) calculation. Too few events are predicted at the lowest x∼10 -4 , especially for topologies with two forward jets. This hints to large contributions at low x from initial state radiation of gluons close to the proton direction and unordered in transverse momentum. The Monte Carlo program in which gluon radiation is generated by the colour dipole model gives a good description of both the three- and the four-jet data in absolute normalisation and shape.

A search for first generation excited neutrinos is performed using the full e(-) p data sample collected by the HI experiment at HERA at a centre-of-mass energy of 319 GeV, corresponding to a total luminosity of 184 pb(-1). The electroweak decays of excited neutrinos nu* -> nu gamma, v* -> nu Z and nu* -> eW with subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for excited neutrino production is found. Mass dependent exclusion limits on nu* production cross sections and on the ratio of the coupling to the compositeness scale f/boolean AND are derived within gauge mediated models. A limit on f/boolean AND A, independent of the relative couplings to the SU(2) and U(1) gauge bosons, is also determined. These limits extend the excluded region to higher masses than has been possible in previous excited neutrino searches. (c) 2008 Elsevier B.V. All rights reserved.

The production of dijets in diffractive deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 61 pb-1. The dijet cross section has been measured for virtualities of the exchanged virtual photon, 5 < Q2 < 100 GeV2, and γ*p centre-of-mass energies, 100 < W < 250 GeV. The jets, identified using the inclusive kT algorithm in the γ*p frame, were required to have a transverse energy E* T,jet > 4 GeV and the jet with the highest transverse energy was required to have E* T,jet > 5 GeV. All jets were required to be in the pseudorapidity range -3.5<η* jet<0. The differential cross sections are compared to leading-order predictions and next-to-leading-order QCD calculations based on recent diffractive parton densities extracted from inclusive diffractive deep inelastic scattering data.

Inclusive D* production is measured in deep-inelastic ep scattering at HERA with the H1 detector. In addition, the production of dijets in events with a D* meson is investigated. The analysis covers values of photon virtuality 2< Q^2 <=100 GeV^2 and of inelasticity 0.05<= y <= 0.7. Differential cross sections are measured as a function of Q^2 and x and of various D* meson and jet observables. Within the experimental and theoretical uncertainties all measured cross sections are found to be adequately described by next-to-leading order (NLO) QCD calculations, based on the photon-gluon fusion process and DGLAP evolution, without the need for an additional resolved component of the photon beyond what is included at NLO. A reasonable description of the data is also achieved by a prediction based on the CCFM evolution of partons involving the k_T-unintegrated gluon distribution of the proton.

Measurements are presented of diffractive open charm production at HERA. The event topology is given by ep→eXY where the system X contains at least one charmed hadron and is well separated by a large rapidity gap from a leading low-mass proton remnant system Y. Two analysis techniques are used for the cross section measurements. In the first, the charm quark is tagged by the reconstruction of a D*±(2010) meson. This technique is used in deep-inelastic scattering (DIS) and photoproduction (γp). In the second, a method based on the displacement of tracks from the primary vertex is used to measure the open charm contribution to the inclusive diffractive cross section in DIS. The measurements are compared with next-to-leading order QCD predictions based on diffractive parton density functions previously obtained from a QCD analysis of the inclusive diffractive cross section at H1. A good agreement is observed in the full kinematic regime, which supports the validity of QCD factorization for open charm production in diffractive DIS and γp.

The average charged track multiplicity and the normalised distribution of the scaled momentum, $\xp$, of charged final state hadrons are measured in deep-inelastic $\ep$ scattering at high $Q^2$ in the Breit frame of reference. The analysis covers the range of photon virtuality $100 < Q^2 < 20 000 \GeV^{2}$. Compared with previous results presented by HERA experiments this analysis has a significantly higher statistical precision and extends the phase space to higher $Q^{2}$ and to the full range of $\xp$. The results are compared with $e^+e^-$ annihilation data and with various calculations based on perturbative QCD using different models of the hadronisation process.

The average charged track multiplicity and the normalised distribution of the scaled momentum, xp, of charged final state hadrons are measured in deep-inelastic ep scattering at high Q2 in the Breit frame of reference. The analysis covers the range of photon virtuality 100 < Q2 < 20 000 GeV2. Compared with previous results presented by HERA experiments this analysis has a significantly higher statistical precision and extends the phase space to higher Q2 and to the full range of xp. The results are compared with e+e− annihilation data and with various calculations based on perturbative QCD using different models of the hadronisation process. Submitted to Phys. Lett. B. F.D. Aaron, A. Aktas, C. Alexa, V. Andreev, B. Antunovic, S. Aplin, A. Asmone, A. Astvatsatourov, S. Backovic, A. Baghdasaryan, P. Baranov, E. Barrelet, W. Bartel, S. Baudrand, M. Beckingham, K. Begzsuren, O. Behnke, O. Behrendt, A. Belousov, N. Berger, J.C. Bizot, M.-O. Boenig, V. Boudry, I. Bozovic-Jelisavcic, J. Bracinik, G. Brandt, M. Brinkmann, V. Brisson, D. Bruncko, F.W. Büsser, A. Bunyatyan, G. Buschhorn, L. Bystritskaya, A.J. Campbell, K.B. Cantun Avila, F. Cassol-Brunner, K. Cerny, V. Cerny, V. Chekelian, A. Cholewa, J.G. Contreras, J.A. Coughlan, G. Cozzika, J. Cvach, J.B. Dainton, K. Daum, M. Deak, Y. de Boer, B. Delcourt, M. Del Degan, J. Delvax, A. De Roeck, E.A. De Wolf, C. Diaconu, V. Dodonov, A. Dubak, G. Eckerlin, V. Efremenko, S. Egli, R. Eichler, F. Eisele, A. Eliseev, E. Elsen, S. Essenov, A. Falkiewicz, P.J.W. Faulkner, L. Favart, A. Fedotov, R. Felst, J. Feltesse, J. Ferencei, L. Finke, M. Fleischer, A. Fomenko, G. Franke, T. Frisson, E. Gabathuler, J. Gayler, S. Ghazaryan, S. Ginzburgskaya, A. Glazov, I. Glushkov, L. Goerlich, M. Goettlich, N. Gogitidze, S. Gorbounov, M. Gouzevitch, C. Grab, T. Greenshaw, B.R. Grell, G. Grindhammer, S. Habib, D. Haidt, M. Hansson, G. Heinzelmann, C. Helebrant, R.C.W. Henderson, H. Henschel, G. Herrera, M. Hildebrandt, K.H. Hiller, D. Hoffmann, R. Horisberger, A. Hovhannisyan, T. Hreus, M. Jacquet, M.E. Janssen, X. Janssen, V. Jemanov, L. Jönsson, D.P. Johnson, A.W. Jung, H. Jung, M. Kapichine, J. Katzy, I.R. Kenyon, C. Kiesling, M. Klein, C. Kleinwort, T. Klimkovich, T. Kluge, A. Knutsson, V. Korbel, P. Kostka, M. Kraemer, K. Krastev, J. Kretzschmar, A. Kropivnitskaya, K. Krüger, M.P.J. Landon, W. Lange, G. Laštovička-Medin, P. Laycock, A. Lebedev, G. Leibenguth, V. Lendermann, S. Levonian, G. Li, L. Lindfeld, K. Lipka, A. Liptaj, B. List, J. List, N. Loktionova, R. Lopez-Fernandez, V. Lubimov, A.-I. Lucaci-Timoce, L. Lytkin, A. Makankine, E. Malinovski, P. Marage, Ll. Marti, M. Martisikova, H.-U. Martyn, S.J. Maxfield, A. Mehta, K. Meier, A.B. Meyer, H. Meyer, H. Meyer, J. Meyer, V. Michels, S. Mikocki, I. Milcewicz-Mika, A. Mohamed, F. Moreau, A. Morozov, J.V. Morris, M.U. Mozer, K. Müller, P. Murı́n, K. Nankov, B. Naroska, Th. Naumann, P.R. Newman, C. Niebuhr, A. Nikiforov, G. Nowak, K. Nowak, M. Nozicka, R. Oganezov, B. Olivier, J.E. Olsson, S. Osman, D. Ozerov, V. Palichik, I. Panagoulias, M. Pandurovic, Th. Papadopoulou, C. Pascaud, G.D. Patel, H. Peng, E. Perez, D. Perez-Astudillo, A. Perieanu, A. Petrukhin, I. Picuric, S. Piec, D. Pitzl, R. Plačakytė, R. Polifka, B. Povh, T. Preda, P. Prideaux, V. Radescu, A.J. Rahmat, N. Raicevic, T. Ravdandorj, P. Reimer, C. Risler, E. Rizvi, P. Robmann, B. Roland, R. Roosen, A. Rostovtsev, Z. Rurikova, S. Rusakov, D. Salek, F. Salvaire, D.P.C. Sankey, M. Sauter, E. Sauvan, S. Schmidt, S. Schmitt, C. Schmitz, L. Schoeffel, A. Schöning, H.-C. Schultz-Coulon, F. Sefkow, R.N. Shaw-West, I. Sheviakov, L.N. Shtarkov, T. Sloan, I. Smiljanic, P. Smirnov, Y. Soloviev, D. South, V. Spaskov, A. Specka, Z. Staykova, M. Steder, B. Stella, J. Stiewe, U. Straumann, D. Sunar, T. Sykora, V. Tchoulakov, G. Thompson, P.D. Thompson, T. Toll, F. Tomasz, T.H. Tran, D. Traynor, T.N. Trinh, P. Truöl, I. Tsakov, B. Tseepeldorj, G. Tsipolitis, I. Tsurin, J. Turnau, E. Tzamariudaki, K. Urban, D. Utkin, A. Valkárová, C. Vallée, P. Van Mechelen, A. Vargas Trevino, Y. Vazdik, S. Vinokurova, V. Volchinski, G. Weber, R. Weber, D. Wegener,

A search for second and third generation scalar and vector leptoquarks produced in ep collisions via the lepton flavour violating processes ep to mu-X and ep to tau-X is performed by the H1 Collaboration at HERA. The full H1 ep data sample taken at a centre-of-mass energy of 319 GeV is used for the analysis, corresponding to an integrated luminosity of 411 pb^-1. No evidence for the production of such leptoquarks is observed in the H1 data. Leptoquarks produced in ep collisions with a coupling strength of lambda=0.3 and decaying with the same coupling strength to a muon-quark pair or a tau-quark pair are excluded at 95% confidence level up to leptoquark masses of 712 GeV and 479 GeV, respectively.

Inclusive D *± production is measured in deep-inelastic ep scattering at HERA with the H1 detector. In addition, the production of dijets in events with a D *± meson is investigated. The analysis covers values of photon virtuality 2 ≤ Q 2 ≤ 100 GeV 2 and of inelasticity 0.05≤y≤0.7. Differential cross sections are measured as a function of Q 2 and x and of various D *± meson and jet observables. Within the experimental and theoretical uncertainties all measured cross sections are found to be adequately described by next-to-leading order (NLO) QCD calculations, based on the photon–gluon fusion process and DGLAP evolution, without the need for an additional resolved component of the photon beyond what is included at NLO. A reasonable description of the data is also achieved by a prediction based on the CCFM evolution of partons involving the k T -unintegrated gluon distribution of the proton.

Inclusive jet production is studied in neutral current deep-inelastic positron–proton scattering at large four momentum transfer squared Q2>150GeV2 with the H1 detector at HERA. Single and double differential inclusive jet cross sections are measured as a function of Q2 and of the transverse energy ET of the jets in the Breit frame. The measurements are found to be well described by calculations at next-to-leading order in perturbative QCD. The running of the strong coupling is demonstrated and the value of αs(MZ) is determined. The ratio of the inclusive jet cross section to the inclusive neutral current cross section is also measured and used to extract a precise value for αs(MZ)=0.1193±0.0014(exp.)−0.0030+0.0047(th.)±0.0016(pdf).

A search for narrow baryonic resonances decaying into (cid:4) (cid:0) (cid:25) (cid:0) or (cid:4) (cid:0) (cid:25) + and their an-tiparticles is carried out with the H1 detector using deep inelastic scattering events at HERA in the range of negative photon four-momentum transfer squared 2 < Q 2 < 100 GeV 2 . No signal for a new baryonic state in the mass range 1600 (cid:0) 2300 MeV is observed in either the doubly charged or the neutral decay channels. The known baryon (cid:4)(1530) 0 is observed through its decay mode into (cid:4) (cid:0) (cid:25) + . Mass/dependent upper limits are given on the ratio of the production rates of new baryonic states, such as the hypothetical pentaquark states (cid:4) (cid:0)(cid:0) 5 q or (cid:4) 05 q , relative to the (cid:4)(1530) 0 baryon state. are no indications of any new baryonic state decaying into (cid:4) (cid:25) in the mass range 1600 (cid:0) 2300MeV. Thus H1 can not con(cid:12)rm the signal reported by the NA49 collaboration. Mass-dependent upper limits at the 95 % C.L. are set on the production ratio of hypothetical states, such as (cid:4) (cid:0)(cid:0) 5 q and (cid:4) 05 q , to the total number of observed (cid:4)(1530) 0 baryons. These limits are comparable to those measured by the ZEUS Collaboration[11].

The production of tau leptons in ep collisions is investigated using data recorded by the H1 detector at HERA in the period 1994–2000. Tau leptons are identified by detecting their decay products, using leptonic and hadronic decay modes. The cross section for the production of tau lepton pairs is measured for the first time at HERA. Furthermore, a search for events with an energetic isolated tau lepton and with large missing transverse momentum is performed. The results are found to be in agreement with the Standard Model predictions.