Search NASA⌕ Search

SEARCH · Search NASA

Results for “INCLUSIVE INTERACTIONS”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Results on the search for the standard model Higgs boson at CMS

A summary of the results from searches for the Standard Model Higgs Boson in the CMS experiment at LHC with data collected from proton-proton collisions at {radical}(s) = 7TeV is presented. The Higgs boson is searched in a multiplicity of decay channels using data samples corresponding to integrated luminosities in the range 4.6 - 4.8 fb{sup -1}. The investigated mass range is 110 - 600 GeV. Results are reported for each channel as well as for their combination.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

ATLAS measurements of soft particle production and diffraction

The ATLAS Collaboration has measured a wide range of properties of soft particle production in {radical}(s) = 900GeV and {radical}(s) = 7TeV proton-proton collisions at the Large Hadron Collider (LHC). These include forward-backward and azimuthal correlations, azimuthal ordering of hadron production, underlying event properties and their dependence on aspects of the hard scattering process. The inelastic and diffractive cross sections have also been measured, using particle forward flow and rapidity gaps. Many of these measurements are used to develop and tune models for soft particle production.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Spin determination of heavy s-channel diphoton resonances at the LHC

Diphoton events at the LHC can provide clean signals of heavy neutral quantum states predicted by New Physics models. These non-standard particles would manifest themselves by s-channel peaks in inclusive distributions in the diphoton invariant mass. Once discovered, the quantum numbers of such a diphoton resonance need to be determined in order to identify the associated non-standard physics, in the first place the spin by an angular analysis of the events. We here discuss this problem by comparing, as competing sources of a diphoton resonance, the spin-2 Randall-Sundrum graviton excitation and a spin-0 scalar exchange, by means of a specific angular-integrated asymmetry predicted theoretically at next-to-leading order in QCD. For the LHC with nominal energy of 14 TeV and integrated luminosity 100 fb{sup -1}, we find that graviton exchange could be discriminated against the scalar one with same mass M{sub R} and events rate, up to M{sub R} Asymptotically-Equal-To 3.2TeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Momentum space dipole amplitude for DIS and inclusive hadron production

We show how the AGBS model, originally developed for deep inelastic scattering applied to HERA data on the proton structure function, can also describe the RHIC data on single inclusive hadron yield for d+Au and p+p collisions through a new simultaneous fit. The single inclusive hadron production is modeled through the color glass condensate, which uses the quark(and gluon) condensate amplitudes in momentum space. The AGBS model is also a momentum space model based on the asymptotic solutions of the BK equation, although a different definition of the Fourier transform is used. This description entirely in transverse momentum of both processes arises for the first time. The small difference between the simultaneous fit and the one for HERA data alone suggests that the AGBS model describes very well both kind of processes and thus emerges as a good tool to investigate the inclusive hadron production data. We use this model for predictions at LHC energies, which agree quite well with available experimental data.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Dilepton resonances in pp (pp) collisions

We analyze dilepton production by considering the contribution of a new neutral gauge boson that are predicted in some extensions of the standard model or alternative models. There are two motivations: the Large Hadron Collider (LHC) is working at an energy regime not yet reached before and the possibility to establish limits for new physics manifest at high energies. The processes analyzed involve dileptons production: p+p{yields}e{sup +}+e{sup -}+X or p+p{yields}{mu}{sup +}+{mu}{sup -}+X, where the new gauge boson Z Prime has a large contribution. We used a Z Prime mass range to obtain lepton distributions that characterize the new contribution and finally we obtain preliminarily discovery potential for a new neutral gauge boson predicted in two versions of the 331 model, showing the possibility to disentangle such versions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Nuclear effects in squark production at the LHC

In this contribution we study the production of squarks. If squarks are found in proton-proton (pp) collisions at the LHC, they might also be produced in collisions involving nuclei (pA and AA collisions). Here we investigate the influence of nuclear effects in the production of squarks in nuclear collisions at the LHC, and estimate the transverse momentum dependence of the nuclear ratios R{sub pA} = (d{sigma}(pA)/d{sub pT})/A(d{sigma}(pp)/d{sub pT}) and R{sub AA} = (d{sigma}(AA)/d{sub pT})/A{sup 2}(d{sigma}(pp)/d{sub pT}). We demonstrate that depending on the magnitude of the nuclear effects, the production of squarks could be enhanced or suppressed, compared to proton-proton collisions at same energies.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Electron-hadron correlations in pp collisions at {radical}(s) = 2.76TeV with the ALICE experiment

In this work we are studying the relative beauty to charm production in pp collisions at {radical}(s) = 2.76TeV, through correlations between electrons from heavy-flavour decay and charged hadrons, with the ALICE detector at the LHC. This study represents a baseline for the analysis in heavy-ion collisions where heavy flavour production is a powerful tool to study the Quark Gluon Plasma (QGP).

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Hadron production at LHC in dipole momentum space

The dipole color approach is the framework that considers the quark-antiquark pair scattering off the target. The rapidity evolution of color dipoles is given by the nonlinear Balitsky-Kovchegov (BK) equation, for which analytical solutions are not yet known. A good way to explore the asymptotic BK solutions is through the traveling wave method of QCD, that uses a correspondence between the BK evolution equation in momentum space and reaction-diffusion physics. Using the traveling wave based AGBS model for the dipole amplitude in momentum space, and within the k{sub t}-factorization formalism, we describe the LHC data on single inclusive hadron yield for p-p collisions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Inclusive production of dijets at the LHeC

We investigate the production of a quark-antiquark pair in inclusive photon-proton scattering, considering distinct gluon distribution functions. The role played by the parton saturation effects is studied for the kinematic regime of the upcoming Large Hadron Electron Collider (LHeC). This proposed lepton-hadron (nucleus) collider will reach energies higher than the available at DESY HERA experiment. This fact will open a new regime to probe the gluon and sea quark distributions in nucleon and on nucleus. In deep inelastic scattering in lepton-hadron colliders, events with two jets and the scattered proton in the final state are predicted to be observable, with an important contribution from charm production. Thus, the contribution from heavy quarks should be investigated in details.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Heavy quark production in the black hole evaporation at LHC

The understanding of Quantum Chromodynamics (QCD) and Quantum Gravity are currently two of the main open questions in Physics. In order to understand these problems some authors proposed the existence of extra dimensions in the Nature. These extra dimensions would be compacted and not visible on the macroscopic world, but the effects would be manifest in ultrarelativistic colision process. In particular, black holes (BH) could be produced in proton-proton colisions in the Large Hadron Collider (LHC) and in future colliders. The BH is an object characterized by its mass and temperature wich also characterizes the evaporation process. All kind of particle should be produced in this process. Our goal in this contribution is to study the BH production in proton - proton collisions at LHC and its evaporation rate in heavy quarks. We present our estimate considering two scenarios (with and without trapped energy corrections) and compare our predictions with those obtained using perturbative QCD. Our results demonstrate that in both scenarios the charm and bottom production in the BH evaporation are smaller than the QCD prediction at LHC. In contrast, the top production is similar or larger than the QCD prediction, if the trapped energy corrections are disregarded.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Lepton production at the LHC from singly- and doubly-charged bilepton

Some extensions of the standard model predict the existence of particles having two units of leptonic charge, known as bileptons. One of such models is based on the SU(3){sub c} Multiplication-Sign SU(3){sub L} Multiplication-Sign U(1){sub X} symmetry group (3-3-1). Our search uses the minimal version of this model, having exotic charges for the quarks and gauge bosons. It predicts the existence of bileptons as vector particles having one unit of electric charge (V{sup {+-}}) or two units of electric charge (Y{sup {+-}{+-}}). Our aim is to establish the signatures for the production of four fermions in pp collisions at the LHC for 7 TeV center of mass energy. We present the total cross section and we show the leptons invariant mass and transverse momentum distributions. We conclude that LHC collider can show a clear signature for a process induced by bileptons as a signal of new physics.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Nonlinear effects in the inclusive inelastic proton-air cross section

In this work we propose a simple model for the total proton-air cross section, which is an improvement of the eikonalized minijet model, with the inclusion of the effects of the first nonlinear corrections to the DGLAP equations. The gluon saturation limits are determined in the DGLAP+GLRMQ approach for the free proton and the inclusive inelastic proton-air cross section is described within the Glauber and multiple scattering approximations. The results are compared with experimental cross sections including recent data obtained by cosmic ray experiments.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

The LHC can probe small x PDFs; the treatment of the infrared region

First, we show how to reduce the sensitivity of the NLO predictions of the Drell-Yan production of low-mass, lepton-pairs, at high rapidity, to the choice of factorization scale. In this way, observations of this process at the LHC can make direct measurements of parton distribution functions in the low x domain; x Less-Than-Or-Equivalent-To 10{sup -4}. Second, we find an inconsistency in the conventional NLO treatment of the infrared region. We illustrate the problem using the NLO coefficient function of Drell-Yan production.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Central diffraction in proton-proton collisions at {radical}(s) = 7TeV with ALICE at LHC

A double-gap topology is used for filtering central-diffractive events from a protonproton minimum-bias data sample at a centre-of-mass energy Central diffraction in proton-proton collisions at {radical}(s) = 7TeV. This topology is defined by particle activity in the ALICE central barrel and absence of particle activity outside. The fraction of events satisfying the double-gap requirement R{sub DG} is found to be 7.63{+-}0.02(st at.){+-}0.87(syst.) Multiplication-Sign 10{sup -4}. The background of this double-gap fraction is estimated by studying the contributions of non-diffractive, single-and double-diffractive dissociation processes as modelled by Monte Carlo event generators, and is found to be about 10%.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Measurement of the inelastic proton-proton cross section with the ATLAS detector

A measurement of the inelastic proton-proton cross-section at centre-of-mass energy of Central diffraction in proton-proton collisions at {radical}(s) = 7TeV using the ATLAS detector at the Large Hadron Collider is presented. Events are selected by requiring hits in scintillator counters mounted in the forward region of the ATLAS detector and the dataset corresponding to an integrated luminosity of 20{mu}b{sup -1}. In addition, the total cross-section is studied as a function of the rapidity gap size measured with the inner detector and calorimetry.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2013

Neutral meson production in pp and Pb-Pb collisions at the LHC with ALICE

The first measurements of the invariant differential cross sections of inclusive {pi}{sup 0} and {eta} meson production with ALICE are presented for pp collisions at {radical}(s) = 0.9 and 7 TeV. Next-to-Leading Order perturbative QCD calculations overestimate the data at {radical}(s) = 7TeV, but are consistent with the {pi}{sup 0} spectrum at {radical}(s) = 0.9TeV and with the measured {pi}{sup 0}/{eta} cross section ratio at {radical}(s) = 7TeV. The nuclear modification factors (R{sub AA}) of {pi}{sup 0} production at different centralities show a strong suppression with respect to pp collisions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Predictions of diffractive cross sections in proton-proton collisions

We review our pre-LHC predictions of the total, elastic, total-inelastic, and diffractive components of proton-proton cross sections at high energies, expressed in the form of unitarized expressions based on a special parton-model approach to diffraction employing inclusive proton parton distribution functions and QCD color factors and compare with recent LHC results.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Analytical representation for pp elastic scattering at 7 TeV

A precise analysis is performed of the recent pp elastic data at 7 TeV in terms of its real and imaginary amplitudes, that are fully disentangled, consistently with dispersion relations for amplitudes and for slopes. Real and imaginary slopes B{sub R} and B{sub I}, treated as independent quantities, influence the whole t-range and the determination of the total cross section {sigma}. The treatment includes extension to the universal perturbative tail at large |t|. Consistency is obtained in the values of {sigma}, ratio {rho}, B{sub R} and B{sub I} determined in forward and full-t approaches.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗