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    First results on ProtoDUNE-SP liquid argon time projection chamber performance from a beam test at the CERN Neutrino Platform
    (IOP Publishing Ltd, 2020-12-01)
    The ProtoDUNE-SP detector is a single-phase liquid argon time projection chamber with an active volume of 7.2 × 6.1 × 7.0 m 3 . It is installed at the CERN Neutrino Platform in a specially-constructed beam that delivers charged pions, kaons, protons, muons and electrons with momenta in the range 0.3 GeV/ c to 7 GeV/ c . Beam line instrumentation provides accurate momentum measurements and particle identification. The ProtoDUNE-SP detector is a prototype for the first far detector module of the Deep Underground Neutrino Experiment, and it incorporates full-size components as designed for that module. This paper describes the beam line, the time projection chamber, the photon detectors, the cosmic-ray tagger, the signal processing and particle reconstruction. It presents the first results on ProtoDUNE-SP's performance, including noise and gain measurements, dE / dx calibration for muons, protons, pions and electrons, drift electron lifetime measurements, and photon detector noise, signal sensitivity and time resolution measurements. The measured values meet or exceed the specifications for the DUNE far detector, in several cases by large margins. ProtoDUNE-SP's successful operation starting in 2018 and its production of large samples of high-quality data demonstrate the effectiveness of the single-phase far detector design.
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    Volume I. Introduction to DUNE
    (IOP Publishing Ltd, 2020-08-01)
    The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay-these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- A nd dual-phase DUNE liquid argon TPC far detector modules. This TDR is intended to justify the technical choices for the far detector that flow down from the high-level physics goals through requirements at all levels of the Project. Volume I contains an executive summary that introduces the DUNE science program, the far detector and the strategy for its modular designs, and the organization and management of the Project. The remainder of Volume I provides more detail on the science program that drives the choice of detector technologies and on the technologies themselves. It also introduces the designs for the DUNE near detector and the DUNE computing model, for which DUNE is planning design reports. Volume II of this TDR describes DUNE's physics program in detail. Volume III describes the technical coordination required for the far detector design, construction, installation, and integration, and its organizational structure. Volume IV describes the single-phase far detector technology. A planned Volume V will describe the dual-phase technology.
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    Volume III. DUNE far detector technical coordination
    (Institute of Physics, 2020-08-01)
    The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay-these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- A nd dual-phase DUNE liquid argon TPC far detector modules. Volume III of this TDR describes how the activities required to design, construct, fabricate, install, and commission the DUNE far detector modules are organized and managed. This volume details the organizational structures that will carry out and/or oversee the planned far detector activities safely, successfully, on time, and on budget. It presents overviews of the facilities, supporting infrastructure, and detectors for context, and it outlines the project-related functions and methodologies used by the DUNE technical coordination organization, focusing on the areas of integration engineering, technical reviews, quality assurance and control, and safety oversight. Because of its more advanced stage of development, functional examples presented in this volume focus primarily on the single-phase (SP) detector module.
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    Volume IV. The DUNE far detector single-phase technology
    (Institute of Physics, 2020-08-01)
    The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay-these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. DUNE is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. Central to achieving DUNE's physics program is a far detector that combines the many tens-of-kiloton fiducial mass necessary for rare event searches with sub-centimeter spatial resolution in its ability to image those events, allowing identification of the physics signatures among the numerous backgrounds. In the single-phase liquid argon time-projection chamber (LArTPC) technology, ionization charges drift horizontally in the liquid argon under the influence of an electric field towards a vertical anode, where they are read out with fine granularity. A photon detection system supplements the TPC, directly enhancing physics capabilities for all three DUNE physics drivers and opening up prospects for further physics explorations. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- A nd dual-phase DUNE liquid argon TPC far detector modules. Volume IV presents an overview of the basic operating principles of a single-phase LArTPC, followed by a description of the DUNE implementation. Each of the subsystems is described in detail, connecting the high-level design requirements and decisions to the overriding physics goals of DUNE.
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    Production of ω mesons in pp collisions at √s=7TeV
    (Institute for Ionics, 2020-12-01)
    Abstract The invariant differential cross section of inclusive $$\omega (782)$$ ω ( 782 ) meson production at midrapidity ( $$|y|<0.5$$ | y | < 0.5 ) in pp collisions at $$\sqrt{s}=7\,\hbox {TeV}$$ s = 7 TeV was measured with the ALICE detector at the LHC over a transverse momentum range of $$2< p_{\mathrm {T}}< 17\,\hbox {GeV}/c$$ 2 < p T < 17 GeV / c . The $$\omega $$ ω meson was reconstructed via its $$\omega \rightarrow \pi ^+\pi ^-\pi ^0$$ ω → π + π - π 0 decay channel. The measured $$\omega $$ ω production cross section is compared to various calculations: PYTHIA 8.2 Monash 2013 describes the data, while PYTHIA 8.2 Tune 4C overestimates the data by about 50%. A recent NLO calculation, which includes a model describing the fragmentation of the whole vector-meson nonet, describes the data within uncertainties below $$6\,\hbox {GeV}/c$$ 6 GeV / c , while it overestimates the data by up to 50% for higher $$p_{\mathrm {T}}$$ p T . The $$\omega /\pi ^0$$ ω / π 0 ratio is in agreement with previous measurements at lower collision energies and the PYTHIA calculations. In addition, the measurement is compatible with transverse mass scaling within the measured $$p_{\mathrm {T}}$$ p T range and the ratio is constant with $$C^{\omega /\pi ^{0}}= 0.67 \pm 0.03 \text {~(stat)~} \pm 0.04 \text {~(sys)~}$$ C ω / π 0 = 0.67 ± 0.03 (stat) ± 0.04 (sys) above a transverse momentum of $$2.5\,\hbox {GeV}/c$$ 2.5 GeV / c .
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    Multiplicity dependence of (multi-)strange hadron production in proton-proton collisions at √s = 13 TeV
    (Springer, 2020-02-01)
    Abstract The production rates and the transverse momentum distribution of strange hadrons at mid-rapidity ( $$\left| y\right| < 0.5$$ y < 0.5 ) are measured in proton-proton collisions at $$\sqrt{s}$$ s = 13 TeV as a function of the charged particle multiplicity, using the ALICE detector at the LHC. The production rates of $$\mathrm{K}^{0}_{S}$$ K S 0 , $$\Lambda $$ Λ , $$\Xi $$ Ξ , and $$\Omega $$ Ω increase with the multiplicity faster than what is reported for inclusive charged particles. The increase is found to be more pronounced for hadrons with a larger strangeness content. Possible auto-correlations between the charged particles and the strange hadrons are evaluated by measuring the event-activity with charged particle multiplicity estimators covering different pseudorapidity regions. When comparing to lower energy results, the yields of strange hadrons are found to depend only on the mid-rapidity charged particle multiplicity. Several features of the data are reproduced qualitatively by general purpose QCD Monte Carlo models that take into account the effect of densely-packed QCD strings in high multiplicity collisions. However, none of the tested models reproduce the data quantitatively. This work corroborates and extends the ALICE findings on strangeness production in proton-proton collisions at 7 TeV.
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    Multiplicity dependence of π, K, and p production in pp collisions at √s=13 TeV
    (Institute for Ionics, 2020-08-01)
    Abstract This paper presents the measurements of $$\pi ^{\pm }$$ π± , $$\mathrm {K}^{\pm }$$ K± , $$\text {p}$$ p and $$\overline{\mathrm{p}} $$ p¯ transverse momentum ( $$p_{\text {T}}$$ pT ) spectra as a function of charged-particle multiplicity density in proton–proton (pp) collisions at $$\sqrt{s}\ =\ 13\ \text {TeV}$$ s=13TeV with the ALICE detector at the LHC. Such study allows us to isolate the center-of-mass energy dependence of light-flavour particle production. The measurements reported here cover a $$p_{\text {T}}$$ pT range from 0.1 to 20 $$\text {GeV}/c$$ GeV/c and are done in the rapidity interval $$|y|<0.5$$ |y|<0.5 . The $$p_{\text {T}}$$ pT -differential particle ratios exhibit an evolution with multiplicity, similar to that observed in pp collisions at $$\sqrt{s}\ =\ 7\ \text {TeV}$$ s=7TeV , which is qualitatively described by some of the hydrodynamical and pQCD-inspired models discussed in this paper. Furthermore, the $$p_{\text {T}}$$ pT -integrated hadron-to-pion yield ratios measured in pp collisions at two different center-of-mass energies are consistent when compared at similar multiplicities. This also extends to strange and multi-strange hadrons, suggesting that, at LHC energies, particle hadrochemistry scales with particle multiplicity the same way under different collision energies and colliding systems.
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    Measurement of Λ (1520) production in pp collisions at √s=7TeV and p–Pb collisions at √sNN=5.02TeV
    (Institute for Ionics, 2020-02-01)
    Abstract The production of the $$\Lambda $$ Λ (1520) baryonic resonance has been measured at midrapidity in inelastic pp collisions at $$\sqrt{s} = 7\ \hbox {TeV}$$ s=7TeV and in p–Pb collisions at $$\sqrt{s_{\mathrm{NN}}} = 5.02\ \hbox {TeV}$$ sNN=5.02TeV for non-single diffractive events and in multiplicity classes. The resonance is reconstructed through its hadronic decay channel $$\Lambda $$ Λ (1520) $$\rightarrow \hbox {pK}^{-}$$ →pK- and the charge conjugate with the ALICE detector. The integrated yields and mean transverse momenta are calculated from the measured transverse momentum distributions in pp and p–Pb collisions. The mean transverse momenta follow mass ordering as previously observed for other hyperons in the same collision systems. A Blast-Wave function constrained by other light hadrons ( $$\pi $$ π , K, $$\hbox {K}_{\mathrm{S}}^0$$ KS0 , p, $$\Lambda $$ Λ ) describes the shape of the $$\Lambda $$ Λ (1520) transverse momentum distribution up to $$3.5\ \hbox {GeV}/c$$ 3.5GeV/c in p–Pb collisions. In the framework of this model, this observation suggests that the $$\Lambda $$ Λ (1520) resonance participates in the same collective radial flow as other light hadrons. The ratio of the yield of $$\Lambda (1520)$$ Λ(1520) to the yield of the ground state particle $$\Lambda $$ Λ remains constant as a function of charged-particle multiplicity, suggesting that there is no net effect of the hadronic phase in p–Pb collisions on the $$\Lambda $$ Λ (1520) yield.
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    Azimuthal correlations of prompt D mesons with charged particles in pp and p–Pb collisions at √sNN=5.02TeV
    (Institute for Ionics, 2020-10-01)
    Abstract The measurement of the azimuthal-correlation function of prompt D mesons with charged particles in pp collisions at $$\sqrt{s} =5.02\ \hbox {TeV}$$ s = 5.02 TeV and p–Pb collisions at $$\sqrt{s_{\mathrm{NN}}} = 5.02\ \hbox {TeV}$$ s NN = 5.02 TeV with the ALICE detector at the LHC is reported. The $$\mathrm{D}^{0}$$ D 0 , $$\mathrm{D}^{+} $$ D + , and $$\mathrm{D}^{*+} $$ D ∗ + mesons, together with their charge conjugates, were reconstructed at midrapidity in the transverse momentum interval $$3< p_\mathrm{T} < 24\ \hbox {GeV}/c$$ 3 < p T < 24 GeV / c and correlated with charged particles having $$p_\mathrm{T} > 0.3\ \hbox {GeV}/c$$ p T > 0.3 GeV / c and pseudorapidity $$|\eta | < 0.8$$ | η | < 0.8 . The properties of the correlation peaks appearing in the near- and away-side regions (for $$\Delta \varphi \approx 0$$ Δ φ ≈ 0 and $$\Delta \varphi \approx \pi $$ Δ φ ≈ π , respectively) were extracted via a fit to the azimuthal correlation functions. The shape of the correlation functions and the near- and away-side peak features are found to be consistent in pp and p–Pb collisions, showing no modifications due to nuclear effects within uncertainties. The results are compared with predictions from Monte Carlo simulations performed with the PYTHIA, POWHEG+PYTHIA, HERWIG, and EPOS 3 event generators.
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    Underlying event properties in pp collisions at √s = 13 TeV
    (Springer, 2020-04-01)
    Abstract This article reports measurements characterizing the Underlying Event (UE) associated with hard scatterings at midrapidity (|η| < 0.8) in pp collisions at $$ \sqrt{s} $$ s = 13 TeV. The hard scatterings are identified by the leading particle, the charged particle with the highest transverse momentum ( $$ {p}_{\mathrm{T}}^{\mathrm{leading}} $$ p T leading ) in the event. Charged-particle number-densities and summed transverse-momentum densities are measured in different azimuthal regions defined with respect to the leading particle direction: Toward, Transverse, and Away. The Toward and Away regions contain the fragmentation products of the hard scatterings in addition to the UE contribution, whereas particles in the Transverse region are expected to originate predominantly from the UE. The study is performed as a function of $$ {p}_{\mathrm{T}}^{\mathrm{leading}} $$ p T leading with three different p T thresholds for the associated particles, $$ {p}_{\mathrm{T}}^{\mathrm{track}} $$ p T track > 0.15, 0.5, and 1.0 GeV/c. The charged-particle density in the Transverse region rises steeply for low values of $$ {p}_{\mathrm{T}}^{\mathrm{leading}} $$ p T leading and reaches a plateau. The results confirm the trend that the charged-particle density in the Transverse region shows a stronger increase with $$ \sqrt{s} $$ s than the inclusive charged-particle density at midrapidity. The UE activity is increased by approximately 20% when going from 7 TeV to 13 TeV pp collisions. The plateau in the Transverse region (5 < $$ {p}_{\mathrm{T}}^{\mathrm{leading}} $$ p T leading < 40 GeV/c) is further characterized by the probability distribution of its charged-particle multiplicity normalized to its average value (relative transverse activity, R T) and the mean transverse momentum as a function of R T. Experimental results are compared to model calculations using PYTHIA 8 and EPOS LHC. The overall agreement between models and data is within 30%. These measurements provide new insights on the interplay between hard scatterings and the associated UE in pp collisions.