The strong coupling constant αs is determined from inclusive jet and dijet cross sections in neutral-current deep-inelastic ep scattering (DIS) measured at HERA by the H1 collaboration using ...next-to-next-to-leading order (NNLO) QCD predictions. The dependence of the NNLO predictions and of the resulting value of αs(mZ) at the Z-boson mass mZ are studied as a function of the choice of the renormalisation and factorisation scales. Using inclusive jet and dijet data together, the strong coupling constant is determined to be αs(mZ)=0.1157(20)exp(29)th. Complementary, αs(mZ) is determined together with parton distribution functions of the proton (PDFs) from jet and inclusive DIS data measured by the H1 experiment. The value αs(mZ)=0.1142(28)tot obtained is consistent with the determination from jet data alone. The impact of the jet data on the PDFs is studied. The running of the strong coupling is tested at different values of the renormalisation scale and the results are found to be in agreement with expectations.
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A measurement of the derivative (∂ lnF2/∂ lnx)Q2≡−λ(x,Q2) of the proton structure function F2 is presented in the low x domain of deeply inelastic positron–proton scattering. For 5×10−5⩽x⩽0.01 and ...Q2⩾1.5GeV2, λ(x,Q2) is found to be independent of x and to increase linearly with lnQ2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, SAZU, SBCE, UL, UM, UPCLJ, UPUK
The inclusive photoproduction of
D
∗
mesons and of
D
∗
-tagged dijets is investigated with the H1 detector at the
ep
collider HERA. The kinematic region covers small photon virtualities
Q
2
<2 GeV
2
...and photon–proton centre-of-mass energies of 100<
W
γp
<285 GeV. Inclusive
D
∗
meson differential cross sections are measured for central rapidities |
η
(
D
∗
)|<1.5 and transverse momenta
p
T
(
D
∗
)>1.8 GeV. The heavy quark production process is further investigated in events with at least two jets with transverse momentum
p
T
(jet)>3.5 GeV each, one containing the
D
∗
meson. Differential cross sections for
D
∗
-tagged dijet production and for correlations between the jets are measured in the range |
η
(
D
∗
)|<1.5 and
p
T
(
D
∗
)>2.1 GeV. The results are compared with predictions from Monte Carlo simulations and next-to-leading order perturbative QCD calculations.
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First measurements are presented of the diffractive cross section sigma(ep) -> eXY at centre-of-mass energies root s of 225 and 252 GeV, together with a precise new measurement at root s of 319 GeV, ...using data taken with the H1 detector in the years 2006 and 2007. Together with previous H1 data at root 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 x 10(-4) <= x(P) <= 3 x 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 Deep-Inelastic 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 Deep-Inelastic Scattering.
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BM@N (Baryonic Matter at Nuclotron) is the first experiment operating and taking data at the Nuclotron/NICA ion-accelerating complex.The aim of the BM@N experiment is to study interactions of ...relativistic heavy-ion beams with fixed targets. We present a technical description of the BM@N spectrometer including all its subsystems.
The 5N neutral particle beamline at the U-70 accelerator (Institute for High Energy Physics), which has been designed to produce a high-intensity neutron beam with the highest possible energy, is ...described. The average neutron energy is ∼51 GeV, and the beam intensity is up to 10
7
neutrons per spill. For several years, this beam has been used to investigate charmed particles and narrow baryon resonances in neutron-nucleus interactions and search for exotic multiquark states with the aid of the EXCHARM spectrometer.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
18.
The H1 forward proton spectrometer at HERA van Esch, P.; Kapichine, M.; Morozov, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2000, Volume:
446, Issue:
3
Journal Article
Peer reviewed
The forward proton spectrometer is part of the H1 detector at the HERA collider. Protons with energies above 500
GeV and polar angles below 1
mrad can be detected by this spectrometer. The main ...detector components are scintillating fiber detectors read out by position-sensitive photo-multipliers. These detectors are housed in the so-called Roman Pots which allow them to be moved close to the circulating proton beam. Four Roman Pot stations are located at distances between 60 and 90
m from the interaction point.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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