Total Inclusive Cross Section Research Articles

Updated predictions for graviton and photon associated production at the LHC

We present updated predictions on the inclusive total cross sections, including the complete next-to-leading order QCD corrections, for the graviton and photon associated production process in the large extra dimensions model at the LHC with a center-of-mass energy of 7 and 8 TeV, using the parameters according to the requirements of the ATLAS and CMS Collaborations. Moreover, we also discuss in detail the dependence on the transverse momentum cut and uncertainties due to the choices of scales and parton distribution functions.

Vh@nnlo—Higgs Strahlung at hadron colliders

A numerical program for the evaluation of the inclusive cross section for associated Higgs production with a massive weak gauge boson at hadron colliders is described, σ(pp/pp̄→HV), V∈{W,Z}. The calculation is performed in the framework of the Standard Model and includes next-to-next-to-leading order QCD as well as next-to-leading order electro-weak effects. Program summaryProgram title: vh@nnloCatalogue identifier: AEOF_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEOF_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 32835No. of bytes in distributed program, including test data, etc.: 206496Distribution format: tar.gzProgramming language: Fortran 77, C++.Computer: Personal computer.Operating system: Unix/Linux, Mac OS.RAM: A few 100 MBClassification: 11.1.External routines: LHAPDF (http://lhapdf.hepforge.org/), CUBA (http://www.feynarts.de/cuba/)Nature of problem:Calculation of the inclusive total cross section for associated Higgs- and W- or Z- boson production at hadron colliders through next-to-next-to-leading order QCD.Solution method:Numerical Monte Carlo integration.Running time:A few seconds for a single set of parameters.

Many-body interactions of neutrinos with nuclei: Observables

Background: The total inclusive cross sections obtained for quasielastic (QE) scattering in the Mini Booster Neutrino Experiment (MiniBooNE) are significantly larger than those calculated by all models based on the impulse approximation and using the world average value for the axial mass of ${M}_{A}\ensuremath{\approx}1\phantom{\rule{0.28em}{0ex}}\mathrm{GeV}$. This discrepancy has led to various, quite different explanations in terms of increased axial masses, changes in the functional form of the axial form factor, increased vector strength in nuclei, and initial two-particle interactions. This is disconcerting since the neutrino energy reconstruction depends on the reaction mechanism.Purpose: We investigate whether exclusive observables, such as nucleon knockout, can be used to distinguish between the various proposed reaction mechanisms. We determine the influence of 2p-2h excitations on the neutrino energy reconstruction.Method: We extend the Giessen Boltzmann--Uehling--Uhlenbeck (GiBUU) model by explicitly incorporating initial 2p-2h excitations.Results: We calculate inclusive cross sections and numbers and spectra of knockout nucleons and show their sensitivity to the presence of 2p-2h initial excitations. We also discuss the influence of 2p-2h excitations on the neutrino energy reconstruction.Conclusions: Inclusive double-differential cross sections, depending only on muon variables, are fairly insensitive to the reaction mechanism. 2p-2h excitations lead to an increase in the number $n$ of knockout nucleons for $n\ensuremath{\geqslant}2$, while only the $n=1$ knockout remains a clean signal of true QE scattering. The spectra of knockout nucleons are also changed, but their shape is hardly affected. In the energy reconstruction, 2p-2h interactions as well as $\ensuremath{\Delta}$ excitations lead to a downward shift of the reconstructed energy; this effect of 2p-2h excitations disappears at higher energies because the 2p-2h influence is spread out over a wider energy range.

Production of twocc¯pairs in double-parton scattering

We discuss production of two pairs of $c \bar c$ within a simple formalism of double-parton scattering (DPS). Surprisingly very large cross sections, comparable to single-parton scattering (SPS) contribution, are predicted for LHC energies. Both total inclusive cross section as a function of energy and differential distributions for $\sqrt{s}$ are shown. We discuss a perspective how to identify the double scattering contribution.

Top-quark mediated effects in hadronic Higgs-Strahlung

Novel contributions to the total inclusive cross section for Higgs-Strahlung in the Standard Model at hadron colliders are evaluated. Although formally of order $\alpha_s^2$, they have not been taken into account in previous NNLO predictions. The terms under consideration are induced by Higgs radiation off top-quark loops and thus proportional to the top-quark Yukawa coupling. At the Tevatron, their effects to HW production are below 1% in the relevant Higgs mass range, while for HZ production, we find corrections between about 1% and 2%. At the LHC, the contribution of the newly evaluated terms to the cross section is typically of the order of 1%-3%. Based on these results, we provide updated predictions for the total inclusive Higgs-Strahlung cross section at the Tevatron and the LHC.

New mechanisms of charm production

We discuss production of charm quarks, mesons as well as nonphotonic electrons in $pp$ scattering at RHIC. The distributions in rapidity and transverse momentum of charm and bottom quarks/antiquarks are calculated in the $k_t$-factorization approach. The hadronization of heavy quarks is done by means of fenomenological fragmentation functions and semileptonic decay functions are found by fitting semileptonic decay data. Good description of the inclusive data at large transverse momenta of electrons is obtained and a missing strength at small transverse momenta of electrons is found. In addition we discuss kinematical correlations between charged leptons from different mechanisms. Reactions initiated by purely QED $\gamma^*\gamma^*$-fusion in elastic and inelastic $pp$ collisions as well as diffractive mechanism of exclusive $c \bar c$ production are included. A good description of the dilepton invariant mass spectrum of the PHENIX collaboration is achieved. Distributions in the dilepton pair transverse momentum and in azimuthal angle between electron and positron are presented. A new mechanism of exclusive production of $c \bar c$ is discussed. Corresponding results are shown and the possibility of its identification is discussed. We discuss also production of two pairs of $c \bar c$ within a simple formalism of double-parton scattering (DPS). Very large cross sections, comparable to single-$c \bar c$ production, are predicted for LHC energies. Both total inclusive cross section as a function of energy and differential distributions are shown. We discuss a perspective how to identify the double scattering contribution.

Measurements of inclusive [formula omitted] production rates as a function of jet transverse momentum in [formula omitted] collisions at [formula omitted

This Letter describes measurements of inclusive W(→eν)+n jet cross sections (n=1–4), presented as total inclusive cross sections and differentially in the nth jet transverse momentum. The measurements are made using data corresponding to an integrated luminosity of 4.2 fb−1 collected by the D0 detector at the Fermilab Tevatron Collider, and achieve considerably smaller uncertainties on W+jets production cross sections than previous measurements. The measurements are compared to next-to-leading order perturbative QCD (pQCD) calculations in the n=1–3 jet multiplicity bins and to leading order pQCD calculations in the 4-jet bin. The measurements are generally in agreement with pQCD calculations, although certain regions of phase space are identified where these predictions could better match the data.

Next-to-leading order QCD predictions forA0γassociated production at the CERN Large Hadron Collider

We calculate the complete next-to-leading-order (NLO) QCD corrections (including SUSY QCD corrections) to the inclusive total cross sections of the associated production processes $pp\rightarrow A^{0}\gamma+X$ in the minimal supersymmetric standard model (MSSM) at the CERN Large Hadron Collider (LHC). Our results show that the enhancement of the total cross sections from the NLO QCD corrections can reach $15%\sim20%$ for 200 GeV$<m_{A}<500$ GeV and $\tan\beta=50$. The scale dependence of the total cross section is improved by the NLO corrections, which is less than 5%. We also show the Monte Carlo simulation results for the $\tau^{+}\tau^{-}+\gamma$ signature including the complete NLO QCD effects, and find an observable signature above the standard model (SM) background for a normal luminosity of 100 fb$^{-1}$ at the LHC.

Supersymmetric Higgs production in gluon fusion

The cross section through gluon fusion is calculated for the production of the light neutral Higgs boson through next-to-leading order QCD within the Minimal Supersymmetric Standard Model. The quark-mediated contributions are taken into account exactly, while for the genuinely supersymmetric terms we use expressions obtained in the limit of large squark, gluino and top quark masses. We present numerical results for the total inclusive cross section as well as for kinematical distributions of the Higgs boson. We also consider the effect of an MSSM-like fourth generation on the total Higgs production cross section.

Higgs plus jet production in bottom quark annihilation at next-to-leading order

The cross section for Higgs + jet production in bottom quark annihilation is calculated through NLO QCD. The five-flavour scheme is used to derive this contribution to the Higgs + jet production cross section which becomes numerically important in the MSSM for large values of tan β . We present numerical results for a proton collider with 14 TeV center-of-mass energy. The NLO matrix elements for d σ / d p T are then combined with the total inclusive cross section in order to derive the integrated cross section with a maximum cut on p T at next-to-next-to-leading order.

Neutron observables from inclusive lepton scattering on nuclei

We analyze new JLAB data for inclusive electron scattering on various targets. Computed and measured total inclusive cross sections in the range $0.3\lesssim x\lesssim 0.95$ show on a logarithmic scale reasonable agreement for all targets. However, closer inspection of the Quasi-Elastic components bares serious discrepancies. EMC ratios which may contain less systematic errors fare the same. The above observations for the new data do not enable the extraction of the magnetic form factor (FF) $G_M^n$ and the Structure Function (SFs) $F_2^n$ of the neutron, although the application of exactly the same analysis to older data had been successful. We add to the above analysis older CLAS collaboration on $F_2^D$. Removing some scattered points, it appears possible to obtain the above mentioned neutron information. We compare our results with others from alternative sources. Particular attention is paid to the A=3 iso-doublet. Present data exist only for $^3$He, but the available input and charge symmetry also enable computations for $^3$H. Their average is the computed iso-scalar part and is compared with the empirical modification of $^3$He towards a fictitious A=3 iso-singlet.

HELICITY DEPENDENT PHOTOPRODUCTION ON THE DEUTERON AND THE GDH SUM RULE ON THE NEUTRON

The first measurements of the helicity dependence for the γd reactions were carried out at MAMI (Mainz) in the energy range E γ=200-800 MeV . The experiment used a 4π detection system, a circularly polarized tagged photon beam and a frozen spin target which provided longitudinally polarized deuterons. Results on both the total inclusive photoabsorption cross section and of the πNN channels will be presented. These data give important information about the the Gerasimov-Drell-Hearn sum rule on the neutron and allow a detailed comparison with state-of-the-art calculations of the γd interaction.

Next-to-leading order QCD predictions for graviton and photon associated production in the large extra dimensions model at the LHC

We present the calculations of the complete next-to-leading order(NLO) QCD corrections to the inclusive total cross sections for the Kaluza-Klein(KK) graviton and photon associated production process $pp \to \gamma G_{KK} + X$ in the large extra dimensions(LED) model at the LHC. We show that the NLO QCD corrections in general enhance the total cross sections and reduce the dependence of the total cross sections on the factorization and renormalization scales. When jet veto is considered, the NLO corrections reduce the total cross sections. We also calculate some important differential cross sections for this process at NLO: the missing transverse momentum distribution, the transverse momentum distribution and the pseudorapidity distribution of photon.

Exclusive double-diffractive production of open charm in proton–proton and proton–antiproton collisions

We calculate differential cross sections for exclusive double diffractive (EDD) production of open charm in proton–proton and proton–antiproton collisions. Sizeable cross sections are found. The EDD contribution constitutes about 1% of the total inclusive cross section for open charm production. A few differential distributions are shown and discussed. The EDD contribution falls faster both with transverse momentum of the c quark/antiquark and the cc¯ invariant mass than in the inclusive case.

Finite top mass effects for hadronic Higgs production at next-to-next-to-leading order

The first four terms of an expansion in mH^2/mt^2 of the total inclusive cross section for Higgs production in gluon fusion are evaluated through next-to-next-to-leading order QCD. A reliable and precise approximation of the full top mass dependence at NNLO is derived and compared to the frequently used heavy-top limit. It is found that both results agree numerically to better than 0.5% in the Higgs mass range of 100-300 GeV. This validates the higher order results for the inclusive Higgs cross section and justifies the heavy-top limit as a powerful tool for Higgs phenomenology at the LHC and the Tevatron.

Helicity dependence of the total inclusive cross section on the deuteron

A measurement of the helicity dependence of the total inclusive photoabsorption cross section on the deuteron was carried out at MAMI (Mainz) in the energy range 200<Eγ<800 MeV. The experiment used a 4π detection system, a circularly polarized tagged photon beam and a frozen spin target which provided longitudinally polarized deuterons. These new results are a significant improvement on the existing data and allow a detailed comparison with state-of-the-art calculations.

Next-to-leading order QCD effects in associated charged Higgs andWboson production in the MSSM at the CERN Large Hadron Collider

We present the calculations of the next-to-leading order (NLO) QCD corrections to the inclusive total cross sections for the associated production of the ${W}^{\ifmmode\pm\else\textpm\fi{}}{H}^{\ensuremath{\mp}}$ through $b\overline{b}$ annihilation in the minimal supersymmetric standard model at the CERN Large Hadron Collider. The NLO QCD corrections can either enhance or reduce the total cross sections, but they generally efficiently reduce the dependence of the total cross sections on the renormalization/factorization scale. The magnitude of the NLO QCD corrections is about 10% in most of the parameter space and can reach 15% in some parameter regions. We also show the Monte Carlo simulation results for the $2j+{\ensuremath{\tau}}_{\mathrm{jet}}+{\mathrm{p\ensuremath{\llap{\not\;}}}}_{T}$ signature from the ${W}^{\ifmmode\pm\else\textpm\fi{}}$ and the ${H}^{\ensuremath{\mp}}$ decays including the NLO QCD effects, and find an observable signal at a $5\ensuremath{\sigma}$ level in some parameter region of the minimal supergravity model.

Extraction of GM n from inclusive electron scattering on D, 4He

We use the relation between Structure Functions (SFs) of nuclei A and nucleons N in order to fomulate a criterion which isolates the QE part out of the total inclusive cross-section. From data points around the QEP we extract the reduced neutron magnetic form factor 〈α n = G M n /μ n G d 〉. The latter shows an unexpected decrease up to Q 2 = 10GeV2, the largest measured.

Parameterized total cross sections for pion production in nuclear collisions

Total inclusive cross sections for neutral and charged pion production in proton–nucleus and nucleus–nucleus reactions have been calculated and compared to experiment. Nucleon–nucleon theoretical cross sections have been scaled up to nuclear collisions using a scaling factor similar to (APAT)2/3, where AP and AT are the nucleon numbers of the projectile and target nuclei. Variations in the power of this scaling factor have been studied and a good fit to experiment is obtained with a small modification of the power. Theoretical cross sections are written in a form that is very suitable for immediate input into transport codes.

Measurement of the Gerasimov-Drell-Hearn Integrand forH2from 200 to 800 MeV

A measurement of the helicity dependence of the total inclusive photoabsorption cross section on the deuteron was carried out at MAMI (Mainz) in the energy range 200<Egamma<800 MeV. The experiment used a 4pi detection system, a circularly polarized tagged photon beam and a frozen-spin target which provided longitudinally polarized deuterons. The contribution to the Gerasimov-Drell-Hearn sum rule for the deuteron determined from the data is 407+/-20(stat)+/-24(syst) mu b for 200<Egamma<800 MeV.