Forward Physics at the LHC: within and beyond the Standard Model
David d'Enterria
备注：
9 pages, 18 figs. Lectures given at the LAWHEP'07 School (Sao Miguel das Missoes, Brazil, 3-7 Dec 2007) to appear in Braz. J. Phys. Also presented in HLPW08 (Spa, Belgium, 6-8 Mar 2008) AIP Conf. Proceeds, to appear; and in HANUC European Grad. School (Jyvaskyla, Finland, 25-29 Aug. 2008)
We review the detection capabilities in the forward direction of the various LHC experiments together with the associated physics programme. A selection of measurements accessible with near-beam instrumentation in various sectors (and extensions) of the Standard Model (SM) is outlined, including QCD (diffractive and elastic scattering, low-x parton dynamics, hadronic Monte Carlos for cosmic-rays), electroweak processes in gamma-gamma interactions, and Higgs physics (vector-boson-fusion and central exclusive production).
The LHCb detector at the LHC offers unique coverage of forward rapidities for studies of Central Exclusive Production (CEP) and soft QCD. CEP measurements allow the investigation of the nature of pomerons, and provide constraints on low-x gluon phenomenology, probing potential saturation effects. Moreover LHCb can test phenomenological models of soft QCD processes, by measuring the production of forward hadrons in pp collisions. In these proceedings the latest results from the LHCb experiment will be presented.
CASTOR: The ALICE forward detector for identification of Centauros and Strangelets in Nucleus-Nucleus Collisions at the LHC
讨论了欧洲核子研究中心（CERN）大型强子对撞机（LHC）ALICE重离子实验中采用超前向探测器的物理动机。提出了一个描述核-核碰撞中半人马座火球形成和衰变的唯象模型。本文描述了CASTOR探测器，它的目的是测量相互作用的强子和光子含量，并以逐事件模式识别非常向前的、富含重子的相空间5.6 < eta < 7.2中的深穿透物体。的量热计的预期响应的模拟结果，特别是奇异的通道，提出。
Precision electroweak tests are a powerful probe of physics beyond the Standard Model, but the sensitivity is limited by the precision with which the $W$ boson mass ($M_W$) has been measured. The Parton Distribution Function (PDF) uncertainties are a potential limitation for measurements of $M_W$ with LHC data. It has recently been pointed out that, thanks to LHCb's unique forward rapidity acceptance, a new measurement of $M_W$ by LHCb can improve this situation. Here we report on a detailed study on the mechanism driving the PDF uncertainty in the LHCb measurement of $M_W$, and propose an app…
Forward $J/ψ$ and very backward jet inclusive production at the LHC
在Mueller-Navelet双喷射产生的精神，我们建议和研究的包容性生产的一个向前$J/ψ$和一个非常落后的喷流在LHC作为一个观察，以揭示高能量remation效应à la BFKL。我们得到了几个预测，这是基于文献中讨论的各种机制来描述生产的$J/ψ$，即NRQCD单重态和八重态的贡献，和颜色蒸发模型。
The LHC Run III will be a crucial run for the two LHC forward experiments: LHCf and FASER. In particular, Run III will be the last run where the LHCf detector can operate and, at the same time, the first run of the new FASER project. The LHCf experiment is dedicated to precise measurements of forward production, necessary to tune hadronic interaction models employed in cosmic-ray physics. In Run III, the experiment will accomplish two fundamental goals: operating in p-p collisions at $\sqrt{s} = $ 14 TeV, it will acquire a ten times larger statistics respect to Run II, in order to have precise…
Dilepton production in proton-proton collision through $γγ$-fusion with one proton scattered elastically while the second produces a hadron jet is considered. Semi-analytical formulas describing the cross section of a muon pair production are presented.
Neutrino fluxes at high rapidity and at high energy are sensitive to QCD dynamics of heavy-flavor production in kinematic regions where measurements have not yet been made. The FASER$ν$ and SND@LHC experiments scheduled for Run 3 at the LHC and the proposed Forward Physics Facility with a suite of experiments during the High-Luminosity LHC phase will probe neutrinos at high pseudorapidity. This short paper reports on recent evaluations of the prompt $ν_τ+\barν_τ$ and $ν_e+\barν_e$ double-differential cross sections in $pp$ collisions at the Large Hadron Collider from the production and decays …
New light particles may be produced in large numbers in the far-forward region at the LHC and then decay to dark matter, which can be detected through its scattering in far-forward experiments. We consider the example of invisibly-decaying dark photons, which decay to dark matter through $A' \to χχ$. The dark matter may then be detected through its scattering off electrons $χe^- \to χe^-$. We consider the discovery potential of detectors placed on the beam collision axis 480 m from the ATLAS interaction point, including an emulsion detector (FASER$ν$2) and, for the first time, a Forward Liquid…
We present a state-of-the-art computation for the production of forward dijets in proton-proton and proton-lead collisions at the LHC, in rapidity domains covered by the ATLAS calorimeter and the planned FoCal extension of the ALICE detector. We use the small-x improved TMD (ITMD) formalism, together with collinearly improved TMD gluon distributions and full b-space Sudakov resummation, and discuss nonperturbative corrections due to hadronization and showers using the Pythia event generator. We observe that forward dijets in proton-nucleus collisions at moderately low pT are excellent probes o…
Charged hadron production in hadron-hadron collisions with longitudinal momentum fraction Feynman-x, x_F, between 0.1 and 0.9 has not been measured above square root s = 63 GeV at the CERN Intersecting Storage Rings. I discuss a way to measure this at the Large Hadron Collider at square root s = 13 TeV, which is 40,000 times higher in equivalent fixed target energy, and important for understanding cosmic ray showers.
Charged particle multiplicities in proton-proton collisions measured in the LHCb detector at a centre-of-mass energy of $\sqrt s$=7 TeV in different windows of pseudorapidity $η$, in the forward region of the vertex detector are studied by using different statistical distributions. Three distributions are compared with the data and the moments of the distributions are calculated. The data constituting two sets, one of minimum bias events and another of hard QCD events are analysed. The distributions considered derive from different functional forms based on underlying interaction dynamics. The…
Theoretical predictions of the prompt atmospheric neutrino flux have large uncertainties associated with charm hadron production, by far the dominant source of prompt neutrinos in the atmosphere. The flux of cosmic rays, with its steeply falling energy spectrum, weights the forward production of charm in the evaluation of the atmospheric neutrino flux at high energies. The current LHCb experiment at CERN constrains charm production in kinematic regions relevant to the prompt atmospheric neutrino flux. The proposed Forward Physics Facility has additional capabilities to detect neutrino fluxes f…
We discuss production of far-forward $D$ mesons/antimesons and neutrinos/antineutrinos from their semileptonic decays in pp-collisions at the LHC. We include the gluon-gluon fusion $gg \to c\bar{c}$, the intrinsic charm (IC) $gc \to gc$ as well as the recombination $gq \to Dc$ partonic mechanisms. The calculations are performed within the $k_T$-factorization approach and the hybrid model using different unintegrated parton distribution functions (uPDFs) for gluons from the literature, as well as within the collinear approach. We compare our results to the LHCb data for forward $D^{0}$-meson pr…
Instituto de Física Gleb Wataghin - Universidade Estadual de Campinas (UNICAMP)（坎皮纳斯州立大学格列布·瓦塔金物理研究所）；Institute of Physics and Mathematics, Federal University of Pelotas（佩洛塔斯联邦大学物理与数学研究所）
The significant neutrino flux at high rapidity at the LHC motivates dedicated forward detectors to study the properties of neutrinos at TeV energies. We investigate magnetic dipole interactions between the active neutrinos and new sterile states at emulsion and liquid argon experiments that could be located in a future Forward Physics Facility (FPF) downstream of the ATLAS interaction point. The up-scattering of neutrinos off electrons produces an electron recoil signature that can probe new regions of parameter space at the High Luminosity LHC (HL-LHC), particularly for liquid argon detectors…
