Measurement of the forward charged particle pseudorapidity density in pp collisions at $$\sqrt{s} = 8$$ s = 8  TeV using a displaced interaction point

Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Baechler, J.; Berardi, V.; Berretti, M.; Bottigli, U.; Bozzo, M.; Brücken, E.; Buzzo, A.; Cafagna, F.; Catanesi, M. G.; Covault, C. E.; Csanád, M.; Csörgő, T.; Deile, M.; Doubek, M.; Eggert, K.; Eremin, V.; Ferro, F.; Fiergolski, A.; García, F.; Georgiev, V.; Gianì, S.; Grzanka, L.; Hammerbauer, J.; Heino, J.; Hilden, T. E.; Karev, A.; Kašpar, J.; Kopal, J.; Kundrát, V.; Lami, S.; Latino, G.; Lauhakangas, R.; Leszko, T.; Lippmaa, É.; Lippmaa, J.; Lokajíček, M.; Losurdo, L.; Vetere, M. Lo; Rodríguez, F. Lucas; Macrı́, M.; Mäki, T.; Mercadante, A.; Minafra, N.; Minutoli, S.; Nemes, F.; Niewiadomski, H.; Oliveri, E.; Oljemark, F.; Orava, R.; Oriunno, M.; Österberg, K.; Palazzi, P.; Peroutka, Zdeněk; Procházka, J.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Ropelewski, L.; Ruggiero, G.; Saarikko, H.; Smajek, J.; Snoeys, W.; Sodzawiczny, T.; Sziklai, J.; Taylor, C.; Turini, N.; Vacek, V.; Welti, J.; Whitmore, J.; Wyszkowski, P.; Zieliński, Krzysztof

doi:10.1140/epjc/s10052-015-3343-7

Cited by 19 publications

(20 citation statements)

References 23 publications

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“…In particular, forward charged hadron production has direct impact on the total number of air-shower muons at the ground, whose measurement shows unexplained excesses compared to model predictions [7]. The rapidities covered in the presented measurement (−6.6 < η < −5.2, still well separated from the beam rapidity y ≈ 9.5) are mostly sensitive to the MPI activity [8].Previous studies of very forward particle production in pp collisions have been carried out at center-of-mass energies of 0.9, 2.76, 7 and 8 TeV by CMS [8,9], at 7 and 8 TeV by TOTEM [9][10][11], and at 7 TeV by LHCf [12,13]. The present paper reports new measurements of inclusive energy spectra at a center-of-mass energy of 13 TeV.…”

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confidence: 71%

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Measurement of the inclusive energy spectrum in the very forward direction in proton-proton collisions at s = 13 $$ \sqrt{s}=13 $$ TeV

Sirunyan¹,

Erbacher²,

Montoya³

et al. 2017

J. High Energ. Phys.

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The differential cross section for inclusive particle production as a function of energy in proton-proton collisions at a center-of-mass energy of 13 TeV is measured in the very forward region of the CMS detector. The measurement is based on data collected with the CMS apparatus at the LHC, and corresponds to an integrated luminosity of 0.34 µb −1 . The energy is measured in the CASTOR calorimeter, which covers the pseudorapidity region −6.6 < η < −5.2. The results are given as a function of the total energy deposited in CASTOR, as well as of its electromagnetic and hadronic components. The spectra are sensitive to the modeling of multiparton interactions in pp collisions, and provide new constraints for hadronic interaction models used in collider and in high energy cosmic ray physics. The CMS collaboration 12 IntroductionParticle production at very forward rapidities (|η| > 5) in high energy hadronic collisions receives contributions from multiparton interactions (MPI), initial-and final-state radiation (from the hardest parton scattering), fragmentation of the so-called "beam remnants", plus diffraction [1]. The sum of all these particle production mechanisms, typically referred to as the "underlying event" [2], is modeled phenomenologically in hadronic Monte Carlo event generators with parameters tuned from the data [3][4][5]. A good understanding of forward particle production is important for a complete description of the final states in proton-proton (pp) interactions at colliders, as well as to accurately simulate extensive air showers induced in the earth atmosphere by very high energy cosmic rays [6]. In particular, forward charged hadron production has direct impact on the total number of air-shower muons at the ground, whose measurement shows unexplained excesses compared to model predictions [7]. The rapidities covered in the presented measurement (−6.6 < η < −5.2, still well separated from the beam rapidity y ≈ 9.5) are mostly sensitive to the MPI activity [8]. Previous studies of very forward particle production in pp collisions have been carried out at center-of-mass energies of 0.9, 2.76, 7 and 8 TeV by CMS [8, 9], at 7 and 8 TeV by TOTEM [9][10][11], and at 7 TeV by LHCf [12, 13]. The present paper reports new measurements of inclusive energy spectra at a center-of-mass energy of 13 TeV. The data are discussed in terms of the production of electrons and photons (mostly from π 0 decays), as well as hadrons (mostly π ± ) in the very forward direction covered by the CASTOR calorimeter of the CMS experiment at the CERN LHC. CASTOR [14] covers the pseudorapidity region −6.6 < η < −5.2, and can distinguish between electromagnetic and hadronic energy depositions. CASTOR is only installed on the negative z-side of CMS, and hence has acceptance at negative pseudorapidities. Because of CASTOR's very forward location, the data are sensitive to parton interactions at very small and large fractional momenta in the proton, x < 10 −4 and x → 1.-1 -

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confidence: 71%

“…Previous studies of very forward particle production in pp collisions have been carried out at center-of-mass energies of 0.9, 2.76, 7 and 8 TeV by CMS [8,9], at 7 and 8 TeV by TOTEM [9][10][11], and at 7 TeV by LHCf [12,13]. The present paper reports new measurements of inclusive energy spectra at a center-of-mass energy of 13 TeV.…”

mentioning

confidence: 78%

Measurement of the inclusive energy spectrum in the very forward direction in proton-proton collisions at s = 13 $$ \sqrt{s}=13 $$ TeV

Sirunyan¹,

Erbacher²,

Montoya³

et al. 2017

J. High Energ. Phys.

Self Cite

View full text Add to dashboard Cite

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“…The highest energy direct measurements were made at the Intersecting Storage Rings and the CERN Antiproton-Proton collider. Note that, the measurements made at the CERN LHC, at 8 TeV, do not cover the full pseudorapidity range [16], and are not included in this work. However, it is worth noting that, if one were to fill in the missing region, the result would be consistent with the fits in Figure 2.…”

Section: Average Charged Multiplicity: < N Ch >mentioning

confidence: 99%

$\langle X_{\text{max}} \rangle $ Uncertainty from Extrapolation of Cosmic Ray Air Shower Parameters

Abbasi

Thomson

2018

Proceedings of 2016 International Conference on Ultra-High Energy Cosmic Rays (UHECR2016)

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In this work we investigate the uncertainties in the prediction of the average shower maximum, < X max >, by the currently used high energy cosmic ray shower simulation models. Recent measurements at the LHC have provided constrains on some of the parameters in these models. However, uncertainties in the prediction of < X max > remain due to extrapolation from accelerator data up to center of mass of 250 TeV. The extrapolation in the elasticity, multiplicity, and p-p cross section from the LHC energy range to 3 × 10 19 eV in a cosmic ray's lab frame is investigated in this proceeding. Our calculation of the uncertainty in < X max > is approximately equal to the difference among the modern models being used in the field.

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“…The result of the measurement is shown in fig. 1.7 [14]. Diffractive processes were studied [15] also during a combined data taking with CMS [16].…”

Section: Figure 15: Compilation Of the Total (Tot) Inelastic (Inel)mentioning

confidence: 99%

“…Diffractive processes were studied [15] also during a combined data taking with CMS [16]. [14] 1.3 Future physics program…”

Section: Figure 15: Compilation Of the Total (Tot) Inelastic (Inel)mentioning

confidence: 99%

Development of a timing detector for the TOTEM experiment at the LHC

Minafra

2017

Eur. Phys. J. Plus

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he LHC is at present the world's largest and highest-energy particle accelerator, hosted at CERN, the European particle physics laboratory near Geneva. The TOTEM experiment was designed to measure the total pp cross section and to study elastic scattering and diffractive dissociation at LHC. The protons that underwent elastic interaction are lightly deflected and, to detect them, TOTEM has installed silicon strip detectors at more than 200 m from the interaction point that can transversally approach the beam down to few millimetres, thanks to a movable piece of the vacuum chamber called Roman Pot.During the first period of operation of the LHC, the TOTEM run campaigns were accomplished during low luminosity dedicated data taking. However, to allow the investigation of rare phenomena, an upgrade program has been proposed by the TOTEM Collaboration, to make possible the data taking at higher luminosities. In particular, a cornerstone of the upgrade program is the inclusion of a fast timing detector in the experimental apparatus to improve the capability of the apparatus to work in high pileup conditions.The main topic of this thesis is the design and the characterization of a fast timing detector for high energy protons. After a survey of the most promising sensor technologies available for fast timing measurements, it was proved, thanks to an extensive campaign of tests using particle beams, that the needed resolution, below 100 ps, was achievable using diamond sensors. In particular, different approaches for the front-end electronics were investigated: some commercially available amplifiers and the timing detector designed by the HADES Collaboration were characterized.Then, a diamond detector, fully compliant with the TOTEM requirements, was designed, tested and prepared for the installation in the RP system. In parallel, 13Introduction other solutions were investigated, such as 3D graphitized diamond sensors and an amplitude dependent amplifier, designed to increase the signal to noise ratio: the gain of the amplifier is small for low amplitude input (noise) and higher in presence of a signal.In particular, the first chapter describes the TOTEM experiment and the main physics results obtained during the first run of the LHC. Then, the physics motivation and the technological challenges of the consolidation and upgrade programs are discussed. Particular attention is given to the impedance optimization of the Roman Pot, described in the second chapter. In fact, the Roman Pot creates a cavity inside the primary vacuum that can resonate at the passage of the beam.This resonance can introduce instabilities in the beam and can, in the worst cases, damage the detector because of the excessive heat generated. The Roman Pot has been optimized in this sense and two new shapes have been designed and realized and, only thanks to this optimization, the Roman Pot can be safely inserted at few millimetres from the beam even at the highest intensities foreseen for the LHC.In the third chapter, the properties of diamond are dis...

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Measurement of the forward charged particle pseudorapidity density in pp collisions at $$\sqrt{s} = 8$$ s = 8 TeV using a displaced interaction point

Cited by 19 publications

References 23 publications

Measurement of the inclusive energy spectrum in the very forward direction in proton-proton collisions at s = 13 $$ \sqrt{s}=13 $$ TeV

Measurement of the inclusive energy spectrum in the very forward direction in proton-proton collisions at s = 13 $$ \sqrt{s}=13 $$ TeV

\(\langle X_{\text{max}} \rangle \) Uncertainty from Extrapolation of Cosmic Ray Air Shower Parameters

Development of a timing detector for the TOTEM experiment at the LHC

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