A detailed analysis is presented of the diffractive deep-inelastic scattering process ep→eXY, where Y is a proton or a low mass proton excitation carrying a fraction 1-xIP>0.95 of the incident proton ...longitudinal momentum and the squared four-momentum transfer at the proton vertex satisfies |t|<1 GeV2. Using data taken by the H1 experiment, the cross section is measured for photon virtualities in the range 3.5≤Q2≤1600 GeV2, triple differentially in xIP, Q2 and β=x/xIP, where x is the Bjorken scaling variable. At low xIP, the data are consistent with a factorisable xIP dependence, which can be described by the exchange of an effective pomeron trajectory with intercept αIP(0)=1.118±0.008(exp.)+0.029-0.010(model). Diffractive parton distribution functions and their uncertainties are determined from a next-to-leading order DGLAP QCD analysis of the Q2 and β dependences of the cross section. The resulting gluon distribution carries an integrated fraction of around 70% of the exchanged momentum in the Q2 range studied. Total and differential cross sections are also measured for the diffractive charged current process e+p→ν̄eXY and are found to be well described by predictions based on the diffractive parton distributions. The ratio of the diffractive to the inclusive neutral current ep cross sections is studied. Over most of the kinematic range, this ratio shows no significant dependence on Q2 at fixed xIP and x or on x at fixed Q2 and β.
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DOBA, FZAB, GEOZS, IJS, IMTLJ, IZUM, KILJ, KISLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The production of leading neutrons, where the neutron carries a large fraction
x
L
of the incoming proton’s longitudinal momentum, is studied in deep-inelastic positron-proton scattering at HERA. The ...data were taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 122 pb
−1
. The semi-inclusive cross section is measured in the phase space defined by the photon virtuality 6<
Q
2
<100 GeV
2
, Bjorken scaling variable 1.5⋅10
−4
<
x
<3⋅10
−2
, longitudinal momentum fraction 0.32<
x
L
<0.95 and neutron transverse momentum
p
T
<0.2 GeV. The leading neutron structure function,
, and the fraction of deep-inelastic scattering events containing a leading neutron are studied as a function of
Q
2
,
x
and
x
L
. Assuming that the pion exchange mechanism dominates leading neutron production, the data provide constraints on the shape of the pion structure function.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
A measurement of the inclusive deep inelastic neutral current
e
+
p
scattering cross section is reported in the region of four-momentum transfer squared, 12 GeV
2
≤
Q
2
≤150 GeV
2
, and Bjorken
x
, ...2×10
−4
≤
x
≤0.1. The results are based on data collected by the H1 Collaboration at the
ep
collider HERA at positron and proton beam energies of
E
e
=27.6 GeV and
E
p
=920 GeV, respectively. The data are combined with previously published data, taken at
E
p
=820 GeV. The accuracy of the combined measurement is typically in the range of 1.3–2%. A QCD analysis at next-to-leading order is performed to determine the parton distributions in the proton based on H1 data.
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DOBA, FZAB, GEOZS, IJS, IMTLJ, IZUM, KILJ, KISLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This paper presents a novel mechatronic approach to modeling, control design, and experimental validation of a two-axis high-accuracy ball screw drive system. At first, a general mathematical model ...is developed by the Lagrange’s equation of Motion to characterize the dynamic behaviors of all the variables for an
N
-degrees of freedom system that includes electric behavior of the DC motors. Thus, the model provides a general framework for the control algorithm design. A robust PD-hyperbolic–type control strategy is proposed based on the representation of a nonlinear dynamic model for the trajectory tracking that solves the problem of regulation and position control. The stability method of Lyapunov is applied; in addition, the asymptotic stability of an equilibrium point is analyzed for the closed-loop dynamic model. The proposed control law ensures the dynamic performance of the closed-loop signals and desired tracking precision. On the other hand, the description of a new and original FPGA-based programmable microprocessor design is introduced which consists of its own design approaches of a hardware/software architecture. Finally, based on a built prototype of a ball screw drive system, experimental tests and simulations with motion trajectory tracking are conducted to verify the proposed general mathematical model and the control law. Experimental results demonstrate an excellent tracking trajectory and desired precision performance, which validates the feasibility and effectiveness of the proposal.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The energy resolution of a highly granular 1 m super(3) analogue scintillator-steel hadronic calorimeter is studied using charged pions with energies from 10GeV to 80GeV at the CERN SPS. The energy ...resolution for single hadrons is determined to be approximately 58%/ square root E/GeV. This resolution is improved to approximately 45%/ square root E/GeV with software compensation techniques. These techniques take advantage of the event-by-event information about the substructure of hadronic showers which is provided by the imaging capabilities of the calorimeter. The energy reconstruction is improved either with corrections based on the local energy density or by applying a single correction factor to the event energy sum derived from a global measure of the shower energy density. The application of the compensation algorithms to GEANT4 simulations yield resolution improvements comparable to those observed for real data.
A measurement is presented of inelastic photo- and electroproduction of
J
/
ψ
mesons in
ep
scattering at HERA. The data were recorded with the H1 detector in the period from 2004 to 2007. Single and ...double differential cross sections are determined and the helicity distributions of the
J
/
ψ
mesons are analysed. The results are compared to theoretical predictions in the colour singlet model and in the framework of non-relativistic QCD. Calculations in the colour singlet model using a
k
T
factorisation ansatz are able to give a good description of the data, while colour singlet model calculations to next-to-leading order in collinear factorisation underestimate the data.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The production of isolated photons in deep-inelastic scattering ep→eγX is measured with the H1 detector at HERA. The measurement is performed in the kinematic range of negative four-momentum transfer ...squared 4<Q
2
<150 GeV
2
and a mass of the hadronic system W
X
>50 GeV. The analysis is based on a total integrated luminosity of 227 pb
-1
. The production cross section of isolated photons with a transverse energy in the range 3<E
T
γ
<10 GeV and pseudorapidity range -1.2<η
γ
<1.8 is measured as a function of E
T
γ
, η
γ
and Q
2
. Isolated photon cross sections are also measured for events with no jets or at least one hadronic jet. The measurements are compared with predictions from Monte Carlo generators modelling the photon radiation from the quark and the electron lines, as well as with calculations at leading and next to leading order in the strong coupling. The predictions significantly underestimate the measured cross sections.
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DOBA, FZAB, GEOZS, IJS, IMTLJ, IZUM, KILJ, KISLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
A prototype module for an International Linear Collider (ILC) detector was built, installed, and tested between 2006 and 2009 at CERN and Fermilab as part of the CALICE test beam program, in order to ...study the possibilities of extending energy sampling behind a hadronic calorimeter and to study the possibilities of providing muon tracking. The "tail catcher/muon tracker" (TCMT) is composed of 320 extruded scintillator strips (dimensions 1000 x 50 x 5 mm super(3)) packaged in 16 one-meter square planes interleaved between steel plates. The scintillator strips were read out with wavelength shifting fibers and silicon photomultipliers. The planes were arranged with alternating horizontal and vertical strip orientations. Data were collected for muons and pions in the energy range 6 GeV to 80 GeV. Utilizing data taken in 2006, this paper describes the design and construction of the TCMT, performance characteristics, and a beam-based evaluation of the ability of the TCMT to improve hadronic energy resolution in a prototype ILC detector. For a typical configuration of an ILC detector with a coil situated outside a calorimeter system with a thickness of 5.5 nuclear interaction lengths, a TCMT would improve relative energy resolution by 6-16% for pions between 20 and 80 GeV.
A search for the single production of doubly-charged Higgs bosons H±± in ep collisions is presented. The signal is searched for via the Higgs decays into a high mass pair of same charge leptons, one ...of them being an electron. The analysis uses up to 118 pb−1 of ep data collected by the H1 experiment at HERA. No evidence for doubly-charged Higgs production is observed and mass dependent upper limits are derived on the Yukawa couplings hel of the Higgs boson to an electron–lepton pair. Assuming that the doubly-charged Higgs only decays into an electron and a muon via a coupling of electromagnetic strength heμ=4παem≃0.3, a lower limit of 141 GeV on the H±± mass is obtained at the 95% confidence level. For a doubly-charged Higgs decaying only into an electron and a tau and a coupling heτ≃0.3, masses below 112 GeV are ruled out.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A measurement of the inclusive
ep
scattering cross section is presented in the region of low momentum transfers, 0.2 GeV
2
≤
Q
2
≤12 GeV
2
, and low Bjorken
x
, 5⋅10
−6
≤
x
≤0.02. The result is based ...on two data sets collected in dedicated runs by the H1 Collaboration at HERA at beam energies of 27.6 GeV and 920 GeV for positrons and protons, respectively. A combination with data previously published by H1 leads to a cross section measurement of a few percent accuracy. A kinematic reconstruction method exploiting radiative
ep
events extends the measurement to lower
Q
2
and larger
x
. The data are compared with theoretical models which apply to the transition region from photoproduction to deep inelastic scattering.
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DOBA, FZAB, GEOZS, IJS, IMTLJ, IZUM, KILJ, KISLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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