Further studies on the physics potential of an experiment using LHC neutrinos

We discuss an experiment to investigate neutrino physics at the LHC, with emphasis on tau flavour. As described in our previous paper Beni et al (2019 J. Phys. G: Nucl. Part. Phys. 46 115008), the detector can be installed in the decommissioned TI18 tunnel, ≈ 480 m downstream the ATLAS cavern, after the first bending dipoles of the LHC arc. The detector intercepts the intense neutrino flux, generated by the LHC beams colliding in IP1, at large pseudorapidity η, where neutrino energies can exceed a TeV. This paper focuses on exploring the neutrino pseudorapity versus energy phase space available in TI18 in order to optimize the detector location and acceptance for neutrinos originating at the pp interaction point, in contrast to neutrinos from pion and kaon decays. The studies are based on the comparison of simulated pp collisions at √s = 13 TeV: PYTHIA events of heavy quark (c and b) production, compared to DPMJET minimum bias events (including charm) with produced particles traced through realistic LHC optics with FLUKA. Our studies favour a configuration where the detector is positioned off the beam axis, slightly above the ideal prolongation of the LHC beam from the straight section, covering 7.4 < η < 9.2. In this configuration, the flux at high energies (0.5-1.5 TeV and beyond) is found to be dominated by neutrinos originating directly from IP1, mostly from charm decays, of which ∼50% are electron neutrinos and ∼5% are tau neutrinos. The contribution of pion and kaon decays to the muon neutrino flux is found small at those high energies. With 150 f b-1 of delivered LHC luminosity in Run 3 the experiment can record a few thousand very high energy neutrino charged current (CC) interactions and over 50 tau neutrino CC events. These events provide useful information in view of a high statistics experiment at HL-LHC. The electron and muon neutrino samples can extend the knowledge of the charm PDF to a new region of x, which is dominated by theory uncertainties. The tau neutrino sample can provide first experience on reconstruction of tau neutrino events in a very boosted regime

Measurement of the inelastic pp cross-section at a centre-of-mass energy of √s = 7 TeV

The cross-section for inelastic proton-proton collisions, with at least one prompt long-lived charged particle of transverse momentum p T > 0.2GeV/c in the pseudorapidity range 2.0 < η < 4.5, is measured by the LHCb experiment at a centre-of-mass energy of √s = 7 TeV. The cross-section in this kinematic range is determined to be σ accinel = 55.0 ± 2.4 mb with an experimental uncertainty that is dominated by systematic contributions. Extrapolation to the full phase space, using PYTHIA 6, yields σ inel = 66.9 ± 2.9 ± 4.4 mb, where the first uncertainty is experimental and the second is due to the extrapolation.S

First measurement of very forward jets with CASTOR in CMS to probe the structure of the proton down to x_Bjorken ≈ 10⁻⁶

Diese Arbeit präsentiert stark vorwärts gerichtete Jets, die zum ersten Mal bei 13 TeV in Proton-Proton Kollisionen gemessen wurden. In hochenergetischen Teilchenkollisionen ist das Berechnen und Simulieren von hadronischen Endzuständen ein in der Theorie immer noch ungelöstes Problem. Effekte wie das sognannte ”underlying event” (UE) haben einen nicht unerheblichen Anteil an der Physik bei solchen Kollisionen. Dies ist dafür verantwortlich, dass der Untergrund bei Beschleunigerexperimenten sowie die Entwicklung von Luftschauern erzeugt durch Höhenstrahlung nur schwer abzuschätzen sind. Um die hadronische Teilchenproduktion zu studieren, wurden hier Jets bei niedriger Strahlintensität während des LHC Run-2 aufgezeichnet. Wegen der günstigen Position des Kalorimeters in der Vorwärtsrichtung liegend ist man in der Lage, bis zu sehr kleinen Werten von x_Bjorken im Proton zu messen. Diese Messung ist sehr empfindlich auf diesen kinematischen Bereich der QCD und eine Möglichkeit die Effekte des UE zu untersuchen. Damit diese Messung gelingt, ist es nötig, die Rekonstruktionssoftware zu verbessern und die genaue Position des Kalorimeters innerhalb von CMS zu bestimmen. Hierfür wurden Daten zum erstem Mal kollaborationsübergreifend mit TOTEM und CMS gemeinsam aufgenommen und ein spezieller TOTEM-CMS Trigger entwickelt. Schlussendlich zeigen die aufgenommenen Daten, dass die Physik im untersuchten Bereich sehr sensitiv auf Effekte wie MultipartonKollisionen reagiert und dass Ereignisse mit zwei Jets in CASTOR dazu geeignet sind, die Kinematik von Partonen bei besonders niedrigen Werten von x_Bjorken zu studieren

Measurement of the inelastic pp cross-section at a centre-of-mass energy of √s = 7 TeV

The cross-section for inelastic proton-proton collisions, with at least one prompt long-lived charged particle of transverse momentum p [subscript T] > 0.2GeV/c in the pseudorapidity range 2.0 < η < 4.5, is measured by the LHCb experiment at a centre-of-mass energy of √s = 7 TeV. The cross-section in this kinematic range is determined to be σ [acc over inel] = 55.0 ± 2.4 mb with an experimental uncertainty that is dominated by systematic contributions. Extrapolation to the full phase space, using Pythia 6, yields σ [subscript inel] = 66.9 ± 2.9 ± 4.4 mb, where the first uncertainty is experimental and the second is due to the extrapolation.National Science Foundation (U.S.

Measurement of the inelastic pp cross-section at a centre-of-mass energy of √s = 7 TeV

The cross-section for inelastic proton-proton collisions, with at least one prompt long-lived charged particle of transverse momentum pT &gt; 0.2GeV/c in the pseudorapidity range 2.0 &#62; η &#62; 4.5, is measured by the LHCb experiment at a centre-ofmass energy of √ s = 7 TeV. The cross-section in this kinematic range is determined to be σ acc inel = 55.0 ± 2.4 mb with an experimental uncertainty that is dominated by systematic contributions. Extrapolation to the full phase space, using Pythia 6, yields σinel = 66.9 ± 2.9 ± 4.4 mb, where the first uncertainty is experimental and the second is due to the extrapolation

Statistical interpretation of exotics monojet data in search of an invisibly decaying Higgs Boson

Includes bibliographical references.Following the recent discovery of a Standard Model Higgs-like particle at the Large Hadron Collider, this study searches for the evidence of invisible decays of this particle. Assuming that this is the Standard Model Higgs boson, its decay to invisible particles is not expected to be measurable in the current data. However, it could have a large contribution from its decay to stable non-Standard Model particles such as the hypothetical dark matter particles. This study corresponds to 4.7 fb!1 of 7 TeV proton-proton collisions and 20.3 fb!1 of 8 TeV proton-proton collisions. At the time of thesis submission, the 8 TeV results were not unblinded by the ATLAS Collaboration, so toy-data are presented here to demonstrate the procedure. The performance of the statistical framework to be used in the combination of the 7 TeV data with the real 8 TeV data is assessed and is found to perform very well. The results are interpreted to set 95 confidence level limits on the branching ratio to invisible particles of the newly discovered Higgs-like particle at a mass of 125 GeV. Limits are also set on the production cross section ⇥ branching ratio of additional Higgs-like particles that decay invisibly in the mass range: 115 GeV to 300 GeV. In the combination of the 7 TeV data and 8 TeV toy-data, an expected (observed) upper limit of0.89 (0.59) is set on the branching ratio to invisible particles of a 125 GeV Higgs boson. In the mass range 115 to 300 GeV, no excess beyond the Standard Model expectation is observed

Measurement of the inelastic pp cross-section at a centre-of-mass energy of root s=7 TeV

The cross-section for inelastic proton-proton collisions, with at least one prompt long-lived charged particle of transverse momentum P-T > 0.2GeV/c in the pseudorapidity range 2.0 <eta <4.5, is measured by the 1:11Cb experiment at a centre-of-mass energy of root s = 7 TeV. The cross-section in this kinematic range is determined to be sigma(accc)(inel) = 55.0 +/- 2.4 nib with an experimental uncertainty that is dominated by systematic contributions. Extrapolation to the full phase space, using PYTHIA 6, yields sigma(inel) = 66.9 +/- 2.9 +/- 4.4 nib, where the first uncertainty is experimental and the second is due to the extrapolation

Measurement of the inelastic pp cross-section at a centre-of-mass energy of root s=7 TeV

The cross-section for inelastic proton-proton collisions, with at least one prompt long-lived charged particle of transverse momentum $p_{\rm T}>0.2$ GeV/$c$ in the pseudorapidity range $2.0<\eta<4.5$, is measured by the LHCb experiment at a centre-of-mass energy of $\sqrt{s}=7$ TeV. The cross-section in this kinematic range is determined to be $\sigma_{\rm inel}^{\rm acc} = 55.0 \pm 2.4$ mb within the spectrometer acceptance with an experimental uncertainty that is dominated by systematic contributions. Extrapolation to the full phase space, using PYTHIA 6, yields $\sigma_{\rm inel} = 66.9 \pm 2.9 \pm 4.4$ mb, where the first uncertainty is experimental and the second is due to the extrapolation.Comment: 15 pages, 2 figure