A simultaneous fit is performed to the $e^+e^-\to Λ_c^+Λ_c^-$ cross section data measured by Belle and BESIII from threshold up to 5.4 GeV. In order to accommodate both the BESIII measurement near threshold and the Belle observation of a resonance $Y(4630)$, we build a composite PDF with a Breit-Wigner resonance and a continuum contribution to model the full cross section line shape of $e^+e^-\to Λ_c^+Λ_c^-$. The fit gives a mass of $M=[4636.1_{-7.2}^{+9.8} ($stat$)\pm 8.0($syst$)]$~MeV/$c^2$, a width of $Γ_{\rm tot}=[34.5_{-16.2}^{+21.0} ($stat$)\pm 5.6($syst$)]$~MeV, and $Γ_{e^+ e^-}\mathcal{B}[Y(4630)\toΛ_c^+Λ_c^-]=[18.3_{-6.1}^{+8.8} ($stat$)\pm 1.1($syst$)]$~eV/$c^2$ for the resonance. The width of $Y(4630)$ from our study is narrower than the previous Belle fit. The mass and width of $Y(4630)$ also show good agreement with a vector resonance $Y(4626)$ recently observed in $D_s^+D_{s1}(2536)^-$ by Belle.
In this article we study a Standard Model extension modifying the top-quark Yukawa coupling to the Higgs boson by allowing a mixture of CP-odd and -even couplings. Single top-quark production in association with an additional Higgs boson provides a natural laboratory to search for such extensions. However, because of the small cross section the experimental analysis is challenging. Already the measurement of the cross section for this process is highly non-trivial. Furthermore, using only cross section measurements, a certain parameter region would escape detection. Using an explicit BSM scena…
We suggest that, if current measurements of inclusive jet production for central rapidities at the LHC are extended to lower transverse momenta, one could define a visible cross section sensitive to the unitarity bound set by the recent determination of the inelastic proton-proton cross section.
The rise of the total, elastic and inelastic hadronic cross sections at high energies is investigated by means of an analytical parametrization, with the exponent of the leading logarithm contribution as a free fit parameter. Using derivative dispersion relations with one subtraction, two different fits to proton-proton and antiproton-proton total cross section and rho parameter data are developed, reproducing well the experimental information in the energy region 5 GeV - 7 TeV. The parametrization for the total cross sections is then extended to fit the elastic (integrated) cross section data…
Multivariate data is often visualized using linear projections, produced by techniques such as principal component analysis, linear discriminant analysis, and projection pursuit. A problem with projections is that they obscure low and high density regions near the center of the distribution. Sections, or slices, can help to reveal them. This paper develops a section pursuit method, building on the extensive work in projection pursuit, to search for interesting slices of the data. Linear projections are used to define sections of the parameter space, and to calculate interestingness by comparin…
New measurements from ATLAS at the LHC are presented on the total cross section at $\sqrt{s}=8$ TeV from elastic scattering using the ALFA sub-detector and on the inelastic cross section at $\sqrt{s}=13$ TeV using the MBTS sub-detector.
High-precision measurements of the Drell-Yan production provide information on different aspects contributing to the process, such as parton distribution functions (PDFs), and comparisons with the current precision reached theoretically on the calculations of the cross sections of such processes. This document describes ATLAS measurements, performed at different centre-of-mass energies, of vector boson (W and Z) cross sections and cross-section ratios. It also discusses measurements of ratios of Z-boson and top-quark pair production cross sections, which provide important information on the pr…
We report on the measurements of inclusive W+jets and Z+jets cross sections in proton-proton collisions at sqrt(s) = 7 TeV with the ATLAS detector. Cross sections, in both the electron and muon decay modes of the bosons, are presented as a function of jet multiplicity, the transverse momentum of the jets and the quantity HT which is the scalar sum of the pT in the event. Measurements are also presented of the ratios of cross sections. The measured cross sections are compared to different particle-level predictions, based on perturbative QCD, where the measured W+3jet cross section is for the f…
Measurement of the ratios of the Z/G* + >= n jet production cross sections to the total inclusive Z/G* cross section in ppbar collisions at sqrt(s) = 1.96 TeV
Measurements of single boson production cross sections are presented. They are based on proton-proton collision data at 8 and 13 TeV recorded with the CMS detector at the LHC. Inclusive and differential cross sections with respect to various observables are measured in various phase spaces. These measurements are compared to perturbative QCD predictions and generally show good agreement with the prediction.
The electron-neutrino charged-current quasi-elastic (CCQE) cross-section on nuclei is an important input parameter to appearance-type neutrino oscillation experiments. Current experiments typically work from the muon neutrino cross-section and apply corrections from theoretical arguments to obtain a prediction for the electron neutrino cross-section, but to date there has been no experimental verification of the estimates for this channel at an energy scale appropriate to such experiments. We present a preliminary result from the MINERvA experiment on the first measurement of an exclusive reac…
A first measurement of the inelastic cross-section of proton-proton collisions at sqrt{s} =7 TeV using the ATLAS detector at the Large Hadron Collider is presented. The measurement is made using scintillators in the forward region of the ATLAS detector. Prospects for elastic cross-section measurements are also discussed.
The Drell-Yan differential cross section is measured in pp collisions at sqrt(s) = 7 TeV, from a data sample collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 36 inverse picobarns. The cross section measurement, normalized to the measured cross section in the Z region, is reported for both the dimuon and dielectron channels in the dilepton invariant mass range 15-600 GeV. The normalized cross section values are quoted both in the full phase space and within the detector acceptance. The effect of final state radiation is also identified. The results are fo…
In this article, we propose a new method for obtaining a Born cross section using visible cross section data. It is assumed that the initial state radiation is taken into account in a visible cross section, while in a Born cross section this effect is ommited. Since the equation that connects Born and visible cross sections is an integral equation of the first kind, the problem of finding its numerical solution is ill-posed. Various regularization-based approaches are often used to solve ill-posed problems, since direct methods usually do not lead to an acceptable result. However, in this arti…
Concepts and results of determinations of the strong coupling constant in hadron collisions are discussed. A recent alpha_s result from the inclusive jet cross section in pp-bar collisions at sqrt(s)=1.96 TeV is presented which is based on perturbative QCD calculations beyond next-to-leading order. Emphasis is put on the consistency of the conceptual approach. Conceptual limitations in the approach of extracting alpha_s from cross section data are discussed and how these can be avoided by using observables that are defined as ratios of cross sections. For one such observable, the multijet cros…
A likelihood-based unfolding method based on Bayes' theorem is presented, with a particular emphasis on the application to differential cross-section measurements in high-energy particle interactions.
Cross sections of reference trigger processes were obtained based on beam property measurements in dedicated luminosity calibration experiments (van der Meer scans). These cross-sections are essential for absolute cross section determinations of physics processes. The reference cross sections are presented for pp collisions at two center of mass energies; 2.76 TeV and 7 TeV, and for Pb-Pb collisions at 2.76 TeV together with a discussion of the systematic uncertainty originating from beam intensity and rate measurement uncertainties.
