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The cross section for ep → e bb̄X in photoproduction is measured with the H1 detector at the ep-collider HERA. The decay channel bb̄ → eeX ′ is selected by identifying the semielectronic decays of the b-quarks. The total production cross section is measured in the kinematic range given by the photon virtuality Q2 ≤ 1GeV, the inelasticity 0.05 ≤ y ≤ 0.65 and(More)
The results of five years of development of the inner tracking system of the HERAB experiment and first experience from the data taking period of the year 2000 are reported. The system contains 184 chambers, covering a sensitive area of about (20 × 20) cm each. The detector is based on microstrip gas counters (MSGCs) with diamond like coated (DLC) glass(More)
We have searched for Theta+(1540) and Xi(--)(1862) pentaquark candidates in proton-induced reactions on C, Ti, and W targets at midrapidity and square root of s = 41.6 GeV. In 2 x 10(8) inelastic events we find no evidence for narrow (sigma approximately 5 MeV) signals in the Theta+ --> pK0(S) and Xi(--) --> Xi- pi- channels; our 95% C.L. upper limits (UL)(More)
The production of isolated photons in deep-inelastic scattering ep→ eγX is measured with the H1 detector atHERA.Themeasurement is performed in the kinematic range of negative four-momentumtransfer squared 4<Q < 150 GeV and amass of the hadronic systemWX > 50 GeV. The analysis is based on a total integrated luminosity of 227 pb. The production cross section(More)
The Compact Muon Solenoid experiment at the Large Hadron Collider at CERN includes a silicon pixel detector as its innermost component. Its main task is the precise reconstruction of charged particles close to the primary interaction vertex. This paper gives an overview of the mechanical requirements and design choices for the barrel pixel detector. The(More)
Photon-proton (γp) interactions with Q < 10 GeV and deep-inelastic scattering (γp) interactions with photon virtualities Q > 5 GeV are studied at the high energy electron-proton collider HERA. The transverse energy flow and relative rates of large rapidity gap events are compared in the two event samples. The observed similarity between γp and γp(More)
Measurements are presented of K 0 meson and baryon production in deep-inelastic positron-proton scattering (DIS) in the kinematic range 10 < Q 2 < 70 GeV 2 and 10 ?4 < x < 10 ?2. The measurements, obtained using the H1 detector at the HERA collider, are discussed in the light of possible mechanisms for increased strangeness production at low Bjorken-x.(More)
We have measured the pi+-->e+ nugamma branching ratio over a wide region of phase space, based on a total of 65 460 events acquired using the PIBETA detector. Minimum-chi2 fits to the measured (E(e+), E(gamma) energy distributions result in the weak form factor value of F(A)=0.0119(1) with a fixed value of F(V)=0.0259. An unconstrained fit yields(More)
A search for squarks in -parity violating supersymmetry is performed in collisions at HERA at a centre of mass energy of GeV, using H1 data corresponding to an integrated luminosity of pb . The direct production of single squarks of any generation in positron-quark fusion via a Yukawa coupling is considered, taking into account -parity violating and(More)
In 1995 the Physik-Institut of the University of Z urich joined the CMS collaboration at the Large Hadron Collider. We participate (i) in the development and construction of the barrel silicon pixel detector (design of the pixels and readout chips and construction of the support structure and cooling system) and (ii) in the design and development of(More)