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(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).A combination is presented of all inclusive deep inelastic cross sections previously published by the H1 and ZEUS collaborations at HERA for neutral and charged current ... scattering for zero beam polarisation. The data were taken at proton beam energies of 920, 820, 575 and 460 GeV and an electron beam energy of 27.5 GeV. The data correspond to an integrated luminosity of about 1 fb... and span six orders of magnitude in negative four-momentum-transfer squared, ..., and Bjorken x. The correlations of the systematic uncertainties were evaluated and taken into account for the combination. The combined cross sections were input to QCD analyses at leading order, next-to-leading order and at next-to-next-to-leading order, providing a new set of parton distribution functions, called HERAPDF2.0. In addition to the experimental uncertainties, model and parameterisation uncertainties were assessed for these parton distribution functions. Variants of HERAPDF2.0 with an alternative gluon parameterisation, HERAPDF2.0AG, and using fixed-flavour-number schemes, HERAPDF2.0FF, are presented. The analysis was extended by including HERA data on charm and jet production, resulting in the variant HERAPDF2.0Jets. The inclusion of jet-production cross sections made a simultaneous determination of these parton distributions and the strong coupling constant possible, resulting in ... An extraction of ... and results on electroweak unification and scaling violations are also presented.

A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities 5.5 < Q 2 < 80 GeV 2 and inelasticities 0.2 < y < 0.6 is presented, using data taken with the H1 detector at HERA, corresponding to an integrated luminosity of 290 pb - 1 . 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 Q 2 . Jet cross sections normalised to the inclusive neutral current DIS cross section in the respective Q 2 -interval are also determined. Previous results of inclusive jet cross sections in the range 150 < Q 2 < 15 , 000 GeV 2 are extended to low transverse jet momenta 5 < P T jet < 7 GeV . 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 Q 2 , the strong coupling constant α s ( M Z ) is determined in next-to-leading order.

A bstract We report the first measurement of the exclusive cross sections e + e − → B B ¯ , e + e − → B B ¯ ∗ , and e + e − → B ∗ B ¯ ∗ in the energy range from 10 . 63 GeV to 11 . 02 GeV. The B mesons are fully reconstructed in a large number of hadronic final states and the three channels are identified using a beam-constrained-mass variable. The shapes of the exclusive cross sections show oscillatory behavior with several maxima and minima. The results are obtained using data collected by the Belle experiment at the KEKB asymmetric-energy e + e − collider.

The strong coupling constant$$\\alpha _\\mathrm{s}$$α s 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$$\\alpha _\\mathrm{s} (m_\\mathrm{Z})$$α s ( m Z ) at the Z -boson mass$$m_Z$$m Z 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$$\\alpha _\\mathrm{s} (m_\\mathrm{Z}) =0.1157\\,(20)_\\mathrm{exp}\\,(29)_\\mathrm{th}$$α s ( m Z ) = 0.1157 ( 20 ) exp ( 29 ) th . Complementary,$$\\alpha _\\mathrm{s} (m_\\mathrm{Z})$$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$$\\alpha _\\mathrm{s} (m_\\mathrm{Z}) =0.1142\\,(28)_\\mathrm{tot}$$α s ( m Z ) = 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.

Signals of QCD instanton-induced processes are searched for in neutral current deep-inelastic scattering at the electron-proton collider HERA in the kinematic region defined by the Bjorken-scaling variable x > 10 - 3 , the inelasticity 0.2 < y < 0.7 and the photon virtuality 150 < Q 2 < 15000   GeV 2 . The search is performed using H1 data corresponding to an integrated luminosity of  351 pb - 1 . No evidence for the production of QCD instanton-induced events is observed. Upper limits on the cross section for instanton-induced processes between 1.5 and 6 pb, at 95 %   confidence level, are obtained depending on the kinematic domain in which instantons could be produced. Compared to earlier publications, the limits are improved by an order of magnitude and for the first time are challenging predictions.

A bstract We present measurements of the branching fractions for the decays B → Kμ + μ − and B → Ke + e − , and their ratio ( R K ), using a data sample of 711 fb − 1 that contains 772 × 10 6 B B ¯ events. The data were collected at the ϒ(4 S ) resonance with the Belle detector at the KEKB asymmetric-energy e + e − collider. The ratio R K is measured in five bins of dilepton invariant-mass-squared ( q 2 ): q 2 ∈ (0 . 1 , 4 . 0) , (4 . 00 , 8 . 12) , (1 . 0 , 6 . 0), (10 . 2 , 12 . 8) and ( > 14 . 18) GeV 2 /c 4 , along with the whole q 2 region. The R K value for q 2 ∈ (1 . 0 , 6 . 0) GeV 2 /c 4 is 1.03 − 0.24 + 0.28 ± 0 . 01. The first and second uncertainties listed are statistical and systematic, respectively. All results for R K are consistent with Standard Model predictions. We also measure CP -averaged isospin asymmetries in the same q 2 bins. The results are consistent with a null asymmetry, with the largest difference of 2.6 standard deviations occurring for the q 2 ∈ (1 . 0 , 6 . 0) GeV 2 /c 4 bin in the mode with muon final states. The measured differential branching fractions, d ℬ /dq 2 , are consistent with theoretical predictions for charged B decays, while the corresponding values are below the expectations for neutral B decays. We have also searched for lepton-flavor-violating B → Kμ ± e ∓ decays and set 90% confidence-level upper limits on the branching fraction in the range of 10 − 8 for B + → K + μ ± e ∓ , and B 0 → K 0 μ ± e ∓ modes.

We report on new flavor tagging algorithms developed to determine the quark-flavor content of bottom ( ) mesons at Belle II. The algorithms provide essential inputs for measurements of quark-flavor mixing and charge-parity violation. We validate and evaluate the performance of the algorithms using hadronic decays with flavor-specific final states reconstructed in a data set corresponding to an integrated luminosity of 62.8 fb-1, collected at the resonance with the Belle II detector at the SuperKEKB collider. We measure the total effective tagging efficiency to be εeff=(30.0±1.2(stat)±0.4(syst))%for a category-based algorithm and εeff=(28.8±1.2(stat)±0.4(syst))%for a deep-learning-based algorithm.

Cross sections for elastic and proton-dissociative photoproduction of J / ψ mesons are measured with the H1 detector in positron-proton collisions at HERA. The data were collected at ep centre-of-mass energies and , corresponding to integrated luminosities of and , respectively. The cross sections are measured as a function of the photon-proton centre-of-mass energy in the range 25< W γp <110 GeV. Differential cross sections d σ /d t , where t is the squared four-momentum transfer at the proton vertex, are measured in the range | t |<1.2 GeV 2 for the elastic process and | t |<8 GeV 2 for proton dissociation. The results are compared to other measurements. The W γp and t -dependences are parametrised using phenomenological fits.

The strong coupling constant α s 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 α s ( m Z ) at the Z -boson mass m Z 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 α s ( m Z ) = 0.1157 ( 20 ) exp ( 29 ) th . Complementary, 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 ) = 0.1142 ( 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.

The H1 Collaboration reports the first measurement of the 1-jettiness event shape observable τ 1 b in neutral-current deep-inelastic electron-proton scattering (DIS). The observable τ 1 b is equivalent to a thrust observable defined in the Breit frame. The data sample was collected at the HERA ep collider in the years 2003–2007 with center-of-mass energy of s = 319 GeV , corresponding to an integrated luminosity of 351.1  pb - 1 . Triple differential cross sections are provided as a function of τ 1 b , event virtuality Q 2 , and inelasticity y , in the kinematic region Q 2 > 150 GeV 2 . Single differential cross sections are provided as a function of τ 1 b in a limited kinematic range. Double differential cross sections are measured, in contrast, integrated over τ 1 b and represent the inclusive neutral-current DIS cross section measured as a function of Q 2 and y . The data are compared to a variety of predictions and include long-standing and more recent Monte Carlo event generators, predictions in fixed-order perturbative QCD where calculations up to O ( α s 3 ) are available for τ 1 b or inclusive DIS, and resummed predictions at next-to-leading logarithmic accuracy matched to fixed order predictions at O ( α s 2 ) . These comparisons reveal sensitivity of the 1-jettiness observable to QCD parton shower and resummation effects, as well as the modeling of hadronization and fragmentation. Within their range of validity, the fixed-order predictions provide a good description of the data. Monte Carlo event generators are predictive over the full measured range and hence their underlying models and parameters can be constrained by comparing to the presented data.