We report measurements of the evolution of the diffuse scattering in a single crystal PbMg1/3Nb2/3O3 as a function of hydrostatic pressure. Upon applying pressure the diffuse scattering intensity ...decreases and is suppressed at about 3 GPa, while no change in the line shape is observed. Correlations between Pb displacements, diffuse scattering and relaxor properties are discussed.
A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities Formula omitted and inelasticities Formula omitted is presented, using data taken ...with the H1 detector at HERA, corresponding to an integrated luminosity of Formula omitted. Double-differential inclusive jet, dijet and trijet cross sections are measured simultaneously and are presented as a function of jet transverse momentum observables and as a function of Formula omitted. Jet cross sections normalised to the inclusive neutral current DIS cross section in the respective Formula omitted-interval are also determined. Previous results of inclusive jet cross sections in the range Formula omitted are extended to low transverse jet momenta Formula omitted. The data are compared to predictions from perturbative QCD in next-to-leading order in the strong coupling, in approximate next-to-next-to-leading order and in full next-to-next-to-leading order. Using also the recently published H1 jet data at high values of Formula omitted, the strong coupling constant Formula omitted is determined in next-to-leading order.
A measurement of elastic deeply virtual Compton scattering γ∗p→γp using e+p and e−p collision data recorded with the H1 detector at HERA is presented. The analysed data sample corresponds to an ...integrated luminosity of 306 pb−1, almost equally shared between both beam charges. The cross section is measured as a function of the virtuality Q2 of the exchanged photon and the centre-of-mass energy W of the γ∗p system in the kinematic domain 6.5<Q2<80 GeV2, 30<W<140 GeV and |t|<1 GeV2, where t denotes the squared momentum transfer at the proton vertex. The cross section is determined differentially in t for different Q2 and W values and exponential t-slope parameters are derived. Using e+p and e−p data samples, a beam charge asymmetry is extracted for the first time in the low Bjorken x kinematic domain. The observed asymmetry is attributed to the interference between Bethe–Heitler and deeply virtual Compton scattering processes. Experimental results are discussed in the context of two different models, one based on generalised parton distributions and one based on the dipole approach.
Abstract
The determination of the strong coupling constant
$$\alpha _{\mathrm{s}} (m_{\mathrm{Z}})$$
α
s
(
m
Z
)
from H1 inclusive and dijet cross section data 1 exploits perturbative QCD predictions ...in next-to-next-to-leading order (NNLO) 2–4. An implementation error in the NNLO predictions was found 4 which changes the numerical values of the predictions and the resulting values of the fits. Using the corrected NNLO predictions together with inclusive jet and dijet data, the strong coupling constant is determined to be
$$\alpha _{\mathrm{s}} (m_{\mathrm{Z}}) =0.1166\,(19)_{\mathrm{exp}}\,(24)_{\mathrm{th}}$$
α
s
(
m
Z
)
=
0.1166
(
19
)
exp
(
24
)
th
. Complementarily,
$$\alpha _{\mathrm{s}} (m_{\mathrm{Z}})$$
α
s
(
m
Z
)
is determined together with parton distribution functions of the proton (PDFs) from jet and inclusive DIS data measured by the H1 experiment. The value
$$\alpha _{\mathrm{s}} (m_{\mathrm{Z}}) =0.1147\,(25)_{\mathrm{tot}}$$
α
s
(
m
Z
)
=
0.1147
(
25
)
tot
obtained is consistent with the determination from jet data alone. Corrected figures and numerical results are provided and the discussion is adapted accordingly.
The measurement of the jet cross sections by the H1 collaboration had been compared to various predictions including the next-to-next-to-leading order (NNLO) QCD calculations which are corrected in ...this erratum for an implementation error in one of the components of the NNLO calculations. The jet data and the other predictions remain unchanged. Eight figures, one table and conclusions are adapted accordingly, exhibiting even better agreement between the corrected NNLO predictions and the jet data.
The measurement of the jet cross sections by the H1 collaboration had been compared to various predictions including the next-to-next-to-leading order (NNLO) QCD calculations which are corrected in ...this erratum for an implementation error in one of the components of the NNLO calculations. The jet data and the other predictions remain unchanged. Eight figures, one table and conclusions are adapted accordingly, exhibiting even better agreement between the corrected NNLO predictions and the jet data.
The determination of the strong coupling constant
α
s
(
m
Z
)
from H1 inclusive and dijet cross section data
1
exploits perturbative QCD predictions in next-to-next-to-leading order (NNLO)
2
–
4
. ...An implementation error in the NNLO predictions was found
4
which changes the numerical values of the predictions and the resulting values of the fits. Using the corrected NNLO predictions together with inclusive jet and dijet data, the strong coupling constant is determined to be
α
s
(
m
Z
)
=
0.1166
(
19
)
exp
(
24
)
th
. Complementarily,
α
s
(
m
Z
)
is determined together with parton distribution functions of the proton (PDFs) from jet and inclusive DIS data measured by the H1 experiment. The value
α
s
(
m
Z
)
=
0.1147
(
25
)
tot
obtained is consistent with the determination from jet data alone. Corrected figures and numerical results are provided and the discussion is adapted accordingly.
Environmental protection is closely related to environmental education. Environmental education is as necessary in the educational system as outside it. The present study, starting from the ...perception of the representatives of the local rural public administration and the citizens of the rural communities on environmental protection issues: (i) highlights the need for information and education in the field of environmental protection, especially about environmental legislation and waste management; (ii) demonstrates the usefulness of environmental educational projects and the use of open educational resources, as resources that can be easily adapted to the real needs of education and information.
Charged particle multiplicity distributions in positron-proton deep inelastic scattering at a centre-of-mass energy Formula omitted GeV are measured. The data are collected with the H1 detector at ...HERA corresponding to an integrated luminosity of 136 pb Formula omitted. Charged particle multiplicities are measured as a function of photon virtuality Formula omitted, inelasticity y and pseudorapidity Formula omitted in the laboratory and the hadronic centre-of-mass frames. Predictions from different Monte Carlo models are compared to the data. The first and second moments of the multiplicity distributions are determined and the KNO scaling behaviour is investigated. The multiplicity distributions as a function of Formula omitted and the Bjorken variable Formula omitted are converted to the hadron entropy Formula omitted, and predictions from a quantum entanglement model are tested.
Exclusive photoproduction of ρ0(770) mesons is studied using the H1 detector at the ep collider HERA. A sample of about 900,000 events is used to measure single- and double-differential cross ...sections for the reaction γp→π+π-Y. Reactions where the proton stays intact (mY=mp) are statistically separated from those where the proton dissociates to a low-mass hadronic system (mp<mY<10GeV). The double-differential cross sections are measured as a function of the invariant mass mππ of the decay pions and the squared 4-momentum transfer t at the proton vertex. The measurements are presented in various bins of the photon–proton collision energy Wγp. The phase space restrictions are 0.5≤mππ≤2.2GeV, |t|≤1.5GeV2, and 20≤Wγp≤80GeV. Cross section measurements are presented for both elastic and proton-dissociative scattering. The observed cross section dependencies are described by analytic functions. Parametrising the mππ dependence with resonant and non-resonant contributions added at the amplitude level leads to a measurement of the ρ0(770) meson mass and width at mρ=770.8-2.7+2.6(tot.)MeV and Γρ=151.3-3.6+2.7(tot.)MeV, respectively. The model is used to extract the ρ0(770) contribution to the π+π- cross sections and measure it as a function of t and Wγp. In a Regge asymptotic limit in which one Regge trajectory α(t) dominates, the intercept α(t=0)=1.0654-0.0067+0.0098(tot.) and the slope α′(t=0)=0.233-0.074+0.067(tot.)GeV-2 of the t dependence are extracted for the case mY=mp.
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