Measurement Of Production Cross Section Research Articles

Hyperon form factors & diquark correlations

Using e+e− annihilation data taken at the CESR collider with the CLEO-c detector, measurements of hyperon pair production cross sections and elastic and transition electromagnetic form factors have been made at the charmonium resonances: ψ(2S), , |Q2| = 13.6 GeV2, ℒ = 48 pb−1; ψ(3770), , |Q2| = 14.2 GeV2, ℒ = 805 pb−1; and ψ(4170), , |Q2| = 17.4 GeV2, ℒ = 586 pb−1. Results with good statistical precision are obtained with high efficiency particle identification. Systematics of pair production cross sections, and form factors with respect to the number of strange quarks in the hyperons are studied, and evidence is presented for effects of diquark correlations in comparative results for Λ0 and Σ0, both of which have the same uds quark content but different isospin.

New measurements of Mαβ, Mγ and total M-shell X-ray production cross sections induced by carbon ions on Bi and Pt targets

In this work X-ray and elastic backscattered spectra from Pt and Bi thin targets were simultaneously measured using C4,3+ ions in the energy range 2.5 MeV to 5 MeV. Mαβ, Mγ and total M-shell X-ray production cross sections were extracted from collected X-ray and backscattered particle spectra using calibrated SDD X-ray and silicon solid state particle detectors. The obtained cross section values are compared to theoretical values employing commonly used datasets for fluorescence yields, emission rates, Coster-Kronig transitions and M-shell ionization cross sections based on the Semi-classical Approximation (United Atom and Separated Atom limits), PWBA (Plane Wave Born approximation), and ECPSSR models. The ISICS code was used for PWBA and ECPSSR calculations.

Measurement of the 43Sc production cross-section with a deuteron beam

43,44Sc/47Sc is one of the most promising theranostic pairs in nuclear medicine. The co-emission of 1157 keV γ-rays with 99.9% branching ratio by 44Sc and the presence of its metastable state 44 mSc push to favour the adoption of 43Sc for Positron Emission Tomography (PET) diagnostic procedures to lighten the dose to the patient and to the personnel. The β+ emitter 43Sc can be produced at a medical cyclotron by proton bombardment of an enriched 43Ca or 46Ti oxide target. 43Sc can be also produced by deuteron bombardment of an enriched 42Ca oxide target. Only a few medical cyclotrons currently in operation offer deuteron beams. Some can be adapted to operate both a proton or a deuteron source. To compare these three production routes, an accurate knowledge of the cross-sections is essential. In this paper, we report on the cross-section measurement of the reaction 42Ca(d,n)43Sc performed at the 6 MV HVEC EN-Tandem of the Ion Beam Physics group at ETH in Zürich. A study of the production yield by using commercially available enriched target materials is also presented.

Measurement of inclusive forward neutron production cross section in proton-proton collisions at sqrt{s}=13 TeV with the LHCf Arm2 detector

In this paper, we report the measurement relative to the production of forward neutrons in proton-proton collisions at sqrt{s}=13 TeV obtained using the LHCf Arm2 detector at the Large Hadron Collider. The results for the inclusive differential production cross section are presented as a function of energy in three different pseudorapidity regions: η > 10.76, 8.99 < η < 9.22 and 8.81 < η < 8.99. The analysis was performed using a data set acquired in June 2015 that corresponds to an integrated luminosity of 0.194 nb−1. The measurements were compared with the predictions of several hadronic interaction models used to simulate air showers generated by Ultra High Energy Cosmic Rays. None of these generators showed good agreement with the data for all pseudorapidity intervals. For η > 10.76, no model is able to reproduce the observed peak structure at around 5 TeV and all models underestimate the total production cross section: among them, QGSJET II-04 shows the smallest deficit with respect to data for the whole energy range. For 8.99 < η < 9.22 and 8.81 < η < 8.99, the models having the best overall agreement with data are SIBYLL 2.3 and EPOS-LHC, respectively: in particular, in both regions SIBYLL 2.3 is able to reproduce the observed peak structure at around 1.5–2.5 TeV.

Measurement of production cross sections in proton induced reactions on natural zirconium

The production cross sections of 90g,92m,95gNb, 86,88,89g,95Zr, 86g,87m,87g,88Y, 85gSr, and 83Rb in a proton induced nuclear reaction of natural zirconium were measured within the proton energy range of 35.7–66.6 MeV at the Korea Multi-purpose Accelerator Complex (KOMAC), Gyeongju, Korea. The excitation functions of radionuclides produced from the natZr(p,x) reactions were determined through a stacked-foil activation method and an off-line γ-ray spectroscopy. A high purity germanium (HPGe) detector was used to measure the induced activities of the radionuclides. The incident beam energy in each foil was calculated from the SRIM code. The proton flux was determined by using the natCu(p,x)62Zn monitor reaction. The measured data were compared with the experimental data in the literature and the data from the TENDL-2017 library based on the TALYS code. The present results are in general agreement with the literature data and in some cases with the calculated data from the TENDL-2017 library. However, in some of the cases, the calculated data from the TENDL-2017 library overestimate or underestimate the experimental data.

Heavy ion PIXE cross sections in Ti, Zn, Nb, Ru and Ta for 4.8–30.0 MeV oxygen and 3.0–12.0 MeV lithium beams

Heavy ion Particle Induced X-ray Emission (PIXE) spectroscopy offers a number of advantages over standard proton PIXE, such as higher yields and therefore higher sensitivity. However, in order to be able to use heavy ion PIXE more detailed measurements of the ionisation and X-ray cross sections for heavy ions are required. This issue was recognised by one of the Coordinated Research Projects (CRP) of the IAEA on MeV Secondary Ion Mass Spectrometry (SIMS). ANSTO took part in this CRP and we measured X-ray production cross sections on a range of samples for oxygen and lithium beam in the energy range of 4.8–30 MeV and 3–12 MeV, respectively. Here we report on these X-ray production cross section measurements and compare the results with theoretical models. Further energy shifts of the characteristic X-ray lines for the different ion-target combinations are presented and discussed.

Measurements of total production cross sections for π++C , π++Al , K++C , and K++Al at 60 GeV/c and π++C and π++Al at 31 GeV/c

This paper presents several measurements of total production cross sections and total inelastic cross sections for the following reactions: $\pi^{+}$+C, $\pi^{+}$+Al, $K^{+}$+C, $K^{+}$+Al at 60 GeV/c, $\pi^{+}$+C and $\pi^{+}$+Al at 31 GeV/c . The measurements were made using the NA61/SHINE spectrometer at the CERN SPS. Comparisons with previous measurements are given and good agreement is seen. These interaction cross sections measurements are a key ingredient for neutrino flux prediction from the reinteractions of secondary hadrons in current and future accelerator-based long-baseline neutrino experiments.

Measurement of L X-ray production cross sections of Ce, Nd, Sm, Eu, Gd, and Dy by impact of 9Be2+ ions with energies in the interval 5.25 MeV to 6.75 MeV

Abstract Measurements of L-subshell X-ray production cross sections from Ce, Nd, Sm, Eu, Gd, and Dy, induced by the irradiation with 9Be2+ ions having energies between 5.25 MeV and 6.75 MeV are presented, with the purpose of comparing them with theoretical predictions from the ECPSSR model with exact integration limits, known as eCPSSR. Adjustments to this theory due to Multiple Ionization and Electron Capture were also considered. It is not possible to determine which of the theoretical models better describes the experimental results, because of their similar predictions.

Magnifying the ATLAS stealth stop splinter: impact of spin correlations and finite widths

In this paper, we recast a “stealth stop” search in the notoriously difficult region of the stop-neutralino Simplified Model parameter space for which mleft({tilde{t}}_1right)-mleft({tilde{upchi}}_1^0right)simeq {m}_t . The properties of the final state are nearly identical for tops and stops, while the rate for stop pair production is mathcal{O} (10%) of that for toverline{t} . Stop searches away from this stealth region have left behind a “splinter” of open parameter space when mleft({tilde{t}}_1right)simeq {m}_t . Removing this splinter requires surgical precision: the ATLAS constraint on stop pair production reinterpreted here treats the signal as a contaminant to the measurement of the top pair production cross section using data from sqrt{s}=7 TeV and 8 TeV in a correlated way to control for some systematic errors. ATLAS fixed mleft({tilde{t}}_1right)simeq {m}_tkern0.5em andkern0.5em mleft({tilde{upchi}}_1^0right)=1 GeV, implying that a careful recasting of these results into the full mleft({tilde{t}}_1right)-mleft({tilde{upchi}}_1^0right) plane is warranted. We find that the parameter space with mleft({tilde{upchi}}_1^0right)lesssim 55 GeV is excluded for mleft({tilde{t}}_1right)simeq {m}_t — although this search does cover new parameter space, it is unable to fully pull the splinter. Along the way, we review a variety of interesting physical issues in detail: (i) when the two-body width is a good approximation; (ii) how assuming the narrow width approximation affects the total rate; (iii ) how the production rate is affected when the wrong widths are used; (iv ) what role propagating the spin correlations consistently through the multi-body decay chain plays in the limits. In addition, we provide a guide to using MadGraph for implementing the full production including finite width and spin correlation effects, and we survey a variety of pitfalls one might encounter.

Event selection for the measurement of the charged current muon antineutrino single pion production cross section in the T2K near detector

Event selection for the measurement of the charged current muon antineutrino single pion production cross section in the T2K near detector

Combination and QCD analysis of charm and beauty production cross-section measurements in deep inelastic ep scattering at HERA

Measurements of open charm and beauty production cross sections in deep inelastic ep scattering at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross sections are obtained in the kinematic range of negative four-momentum transfer squared of the photon 2.5~hbox {GeV}^2le Q^2 le 2000, hbox {GeV}^2 and Bjorken scaling variable 3 cdot 10^{-5} le x_mathrm{Bj} le 5 cdot 10^{-2}. The combination method accounts for the correlations of the statistical and systematic uncertainties among the different datasets. Perturbative QCD calculations are compared to the combined data. A next-to-leading order QCD analysis is performed using these data together with the combined inclusive deep inelastic scattering cross sections from HERA. The running charm- and beauty-quark masses are determined as m_c(m_c) = 1.290^{+0.046}_{-0.041} mathrm{(exp/fit)}{}^{+0.062}_{-0.014} mathrm{(model)}{}^{+0.003}_{-0.031} mathrm{(parameterisation)} GeV and m_b(m_b) = 4.049^{+0.104}_{-0.109} mathrm{(exp/fit)}{}^{+0.090}_{-0.032} mathrm{(model)}{}^{+0.001}_{-0.031} mathrm{(parameterisation)}~mathrm{GeV}.

Measurement of 99Mo production cross-section from the 100Mo(n,2n) reaction with quasi monoenergetic neutron based on the 9Be(p,n) reaction

The production cross-section of the medical isotope, 99Mo from the enriched 100Mo(n,2n) reaction with the average neutron energies of 21.9 and 26.5 MeV has been determined for the first time by using an off-line γ-ray spectrometric technique. The average neutron energies were generated by using the 9Be(p,n) reaction with the proton energies of 35 and 45 MeV from the MC50 cyclotron of the Korea Institute of Radiological and Medical Sciences (KIRAMS) at Seoul, South Korea. The 100Mo(n,2n) reaction cross-section as a function of neutron energy was also calculated theoretically by using the computer code TALYS-1.8 and EMPIRE-3.2 Malta. The experimental results are in close agreement with the theoretical values from TALYS-1.8. However, the present data at the neutron energy of 21.9 MeV is slightly lower and at 26.5 MeV is higher than the values from EMPIRE-3.2 Malta.

Measurement of forward photon production cross-section in proton–proton collisions at [formula omitted] with the LHCf detector

In this paper, we report the production cross-section of forward photons in the pseudorapidity regions of η>10.94 and 8.99>η>8.81, measured by the LHCf experiment with proton–proton collisions at s=13TeV. The results from the analysis of 0.191nb−1 of data obtained in June 2015 are compared to the predictions of several hadronic interaction models that are used in air-shower simulations for ultra-high-energy cosmic rays. Although none of the models agree perfectly with the data, EPOS-LHC shows the best agreement with the experimental data among the models.

Highlights of top quark measurements in hadronic final states at ATLAS

Measurements of inclusive and differential top quark production cross sections in hadronic final states, including hadronic τ decays, in proton-proton collisions with the ATLAS detector at the Large Hadron Collider are presented at center-of-mass energies of 7, 8 and 13 TeV. The inclusive cross section measurements reach high precision and are compared to other decay modes and the best available theoretical calculations. Differential measurements of the kinematic properties of top quark events are also discussed. These measurements use boosted top quarks, probing our understanding of top quark production in the TeV regime.

Measurement of photon production cross sections also in association with jets with the ATLAS detector

The production of prompt isolated photons at hadron colliders provides a stringent test of perturbative QCD and can be used to probe the proton structure. The production of prompt photons in association with jets provides an additional testing ground for perturbative QCD with a hard colourless probe less affected by hadronisation effects than jet production. At the LHC, the ATLAS collaboration has performed precise measurements of the inclusive production of isolated prompt photons at a centre-of-mass energy of 13 TeV. The dynamics of isolated-photon plus jet production in pp collisions at a centre-of-mass energy of 8 TeV have also been measured. In addition, the integrated and differential cross sections for isolated photon pairs at a centre-of-mass energy of 8 TeV have been measured. The results are compared with state-of-the art theory predictions at next-to-leading order in perturbative QCD.

Measurements of Charged-particle Production Cross-sections in Nuclear Reactions for Heavy-ion Radiation Therapy

Measurements of Charged-particle Production Cross-sections in Nuclear Reactions for Heavy-ion Radiation Therapy

αs from top-quark pair production at hadron colliders

The strong coupling constant αs(MZ) is determined using inclusive top-quark pair production cross section measurements performed at the LHC and at the Tevatron. Individual values of αs(MZ) are extracted from measurements of different experiments at several centre-of-mass energies, using QCD predictions complete in NNLO perturbation theory, supplemented with NNLL approximations to all orders, and suitable sets of parton distribution functions. These values are then combined using a likelyhood-based approach, with special emphasis on a consistent treatment of systemtic uncertainties and their correlations. The final combined result is αs(MZ)=0.1177−0.0036+0.0034.

Measurement of the inclusive-isolated prompt-photon cross section in pp¯ collisions using the full CDF data set

A measurement of the inclusive production cross section of isolated prompt photons in proton-antiproton collisions at center-of-mass energy s=1.96 TeV is presented. The results are obtained using the full Run II data sample collected with the Collider Detector at the Fermilab Tevatron, which corresponds to an integrated luminosity of 9.5 fb−1. The cross section is measured as a function of photon transverse energy, ETγ, in the range 30<ETγ<500 GeV and in the pseudorapidity region |ηγ|<1.0. The results are compared with predictions from parton-shower Monte Carlo models at leading order in QCD and from next-to-leading-order perturbative QCD calculations. The latter show good agreement with the measured cross section.Received 1 March 2017DOI:https://doi.org/10.1103/PhysRevD.96.092003© 2017 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasParticle phenomenaParticles & Fields

Determination of the strong coupling constant alpha _s left( m_Z right) from measurements of the total cross section for top\u2013antitop-quark production

We present a determination of the strong coupling constant alpha _s left( m_Z right) using inclusive top-quark pair production cross section measurements performed at the LHC and at the Tevatron. Following a procedure first applied by the CMS Collaboration, we extract individual values of alpha _s left( m_Z right) from measurements by different experiments at several centre-of-mass energies, using QCD predictions complete in NNLO perturbation theory, supplemented with NNLL approximations to all orders, and suitable sets of parton distribution functions. The determinations are then combined using a likelihood-based approach, where special emphasis is put on a consistent treatment of theoretical uncertainties and of correlations between various sources of systematic uncertainties. Our final combined result is alpha _s left( m_Z right) =0.1177^{+0.0034{}}_{-0.0036{}}.

Electroweak diboson production at ATLAS

This paper is giving an overview of recent ATLAS results on the production cross sections of gauge boson pairs decaying leptonically using data from pp collisions at √s = 13 TeV for ZZ and at √s = 8 TeV for W ± Z and W ± W ± at the LHC at CERN. The cross sections are found to be in agreement with the expectations from the Standard Model within the estimated uncertainties. The production cross section measurements also allow for studies of anomalous triple and quartic gauge couplings for which 95% confidence level limits are set.