Search

Axionlike particles (ALPs) emerge from spontaneously broken global symmetries in high energy extensions of the Standard Model (SM). This causes ALPs to be among the objectives of future experiments that intend to search for new physics beyond the SM. We discuss the reach of future pp collider FCC-hh in probing the ALP model parameters through top quark pair production associated with ALP ( t t ¯ + ALP ) in a model-independent approach. The search is performed in the semi-leptonic decay mode of t t ¯ and the analysis is performed using a parametric simulation of the detector response for a projected integrated luminosity of 30 ab − 1 . It is shown that t t ¯ + ALP production at the FCC-hh is a promising channel with significant sensitivity to probe the ALP coupling with gluons. The ALP coupling with gluons obtained from HL-LHC and other experiments is presented for comparison. [ABSTRACT FROM AUTHOR]

PUMA, antiProton Unstable Matter Annihilation, is a nuclear-physics experiment at CERN aiming at probing the surface properties of stable and rare isotopes by use of low-energy antiprotons. Low-energy antiprotons offer a very unique sensitivity to the neutron and proton densities at the annihilation site, i.e. in the tail of the nuclear density. Today, no facility provides a collider of low-energy radioactive ions and low-energy antiprotons: while not being a collider experiment, PUMA aims at transporting one billion antiprotons from ELENA, the Extra-Low-ENergy Antiproton ring, to ISOLDE, the rare-isotope beam facility of CERN. PUMA will enable the capture of low-energy antiprotons by short-lived nuclei and the measurement of the emitted radiations. In this way, PUMA will give access to the so-far largely unexplored isospin composition of the nuclear-radial-density tail of radioactive nuclei. The motivations, concept and current status of the PUMA experiment are presented. [ABSTRACT FROM AUTHOR]

This paper provides an overview of the problems, challenges, and the advanced simulation techniques used to study and plan complex interventions in radiation areas at CERNs Large Hadron Collider and its future upgrade to the High-Luminosity Large Hadron Collider. The operational radiation protection aspects are supported by state of the art simulations by means of the FLUKA Monte Carlo code and estimates conducted via other tools such as ActiWiz and SESAME, used within the HSE-RP group. [ABSTRACT FROM AUTHOR]

We show that only 10 (17) CP-odd operators of the SMEFT give the leading, i.e. least suppressed by the new physics scale, CP-violating contributions once we assume that all fermions are massless but the top (and bottom) quark(s). We start with a short review of previous analyses focusing on operators of our reduced basis and list different observables probing their CP violating effects by direct measurements at colliders and by indirect measurements in low-energy observables. Since CP-odd operators typically lead to phase space suppressed interferences, we quantify the efficiency to revive the interference for various observables found in the literature but also for new observables in diboson production. Our new observables are found to be more efficient on the whole experimental fiducial phase space and are complementary to those presented so far as they probe different combinations of operators and get their sensitivities from different regions of the phase space. [ABSTRACT FROM AUTHOR]

The associated production of a Higgs boson and a top-quark pair is important for probing the Yukawa coupling of the top quark, and calls for better theoretical modeling. In this paper, we calculate the two-loop infrared divergences in t t ¯ H production at hadron colliders. To do that we compute the one-loop amplitudes to higher orders in the dimensional regulator ϵ. Numeric results for the infrared poles are given as a reference at several representative phase-space points. The result in this work serves as a part of the ongoing efforts towards the t t ¯ H cross sections at the next-to-next-to-leading order. [ABSTRACT FROM AUTHOR]

Machine learning algorithms are growing increasingly popular in particle physics analyses, where they are used for their ability to solve difficult classification and regression problems. While the tools are very powerful, they may often be under- or mis-utilised. In the following, we investigate the use of gradient boosting techniques as applicable to a generic particle physics problem. We use as an example a Beyond the Standard Model smuon collider analysis which applies to both current and future hadron colliders, and we compare our results to a traditional cut-and-count approach. In particular, we interrogate the use of metrics in imbalanced datasets which are characteristic of high energy physics problems, offering an alternative to the widely used area under the curve (auc) metric through a novel use of the F-score metric. We present an in-depth comparison of feature selection and investigation using a principal component analysis, Shapley values, and feature permutation methods in a way which we hope will be widely applicable to future particle physics analyses. Moreover, we show that a machine learning model can extend the 95% confidence level exclusions obtained in a traditional cut-and-count analysis, while potentially bypassing the need for complicated feature selections. Finally, we discuss the possibility of constructing a general machine learning model which is applicable to probe a two-dimensional mass plane. [ABSTRACT FROM AUTHOR]

A novel approach to reconstruct inclusive B ¯ → X s ℓ + ℓ - decays is presented. The method relies on isopsin symmetry to extrapolate the semi-inclusive signature X b → K + ℓ + ℓ - X to the fully inclusive rate in B + and B 0 decays. We investigate the possibility to measure branching fractions and other observables such as lepton universality ratios and C P asymmetries. As a proof of concept, fast simulation is used to compare the X b → K + ℓ + ℓ - X signature with a fully inclusive approach. Several experimental advantages are seen which have the potential to make measurements of inclusive B ¯ → X s ℓ + ℓ - decays tractable at a hadron collider. [ABSTRACT FROM AUTHOR]

We propose a new observable for the measurement of the forward–backward asymmetry (A FB) in Drell–Yan lepton production. At hadron colliders, the A FB distribution is sensitive to both the electroweak (EW) fundamental parameter sin 2 θ W , the weak mixing angle, and the parton distribution functions (PDFs). Hence, the determination of sin 2 θ W and the updating of PDFs by directly using the same A FB spectrum are strongly correlated. This correlation would introduce large bias or uncertainty into both precise measurements of EW and PDF sectors. In this article, we show that the sensitivity of A FB on sin 2 θ W is dominated by its average value around the Z pole region, while the shape (or gradient) of the A FB spectrum is insensitive to sin 2 θ W and contains important information on the PDF modeling. Accordingly, a new observable related to the gradient of the spectrum is introduced, and demonstrated to be able to significantly reduce the potential bias on the determination of sin 2 θ W when updating the PDFs using the same A FB data. [ABSTRACT FROM AUTHOR]

We present sensitivity projections for discovering a heavy resonance decaying to electron and muon pairs and for probing the charged lepton nonuniversality in such decays at the High Luminosity Large Hadron Collider (HL-LHC) and hadron-hadron Future Circular Collider (FCC-hh). The analysis takes into account the expected differences in the reconstruction efficiencies and the di-lepton mass resolutions for di-electron and di-muon final states. We demonstrate how the analyses at HL-LHC naturally pave the way for a FCC-hh machine thereby underlining its importance. [ABSTRACT FROM AUTHOR]

We summarize the potential charged lepton flavor violation (LFV) from neutrino mass relevant models, for instance the seesaw mechanisms. In particular, we study, in a model-dependent way, the LFV signals at the high-energy hadron and lepton colliders originating from the beyond standard model (BSM) neutral scalar H, doubly charged scalar H ± ± , heavy neutrino N, heavy W R boson, and the Z ′ boson. For the neutral scalar, doubly charged scalar and Z ′ boson, the LFV signals originate from the (effective) LFV couplings of these particles to the charged leptons, while for the heavy neutrino N and W R boson, the LFV effects are from flavor mixing in the neutrino sector. We consider current limits on these BSM particles and estimate their prospects at future high-energy hadron and lepton colliders. [ABSTRACT FROM AUTHOR]

The analytical expressions of the mixed QCD-EW corrections to on-shell Z boson inclusive production cross section at hadron colliders are presented, together with computational details. The results are given in terms of polylogarithmic functions and elliptic integrals. The impact on the prediction of the Z boson production total cross section is discussed, comparing different proton parton density sets. [ABSTRACT FROM AUTHOR]

The production of dark matter particles from confining dark sectors may lead to many novel experimental signatures. Depending on the details of the theory, dark quark production in proton-proton collisions could result in semivisible jets of particles: collimated sprays of dark hadrons of which only some are detectable by particle collider experiments. The experimental signature is characterised by the presence of reconstructed missing momentum collinear with the visible components of the jets. This complex topology is sensitive to detector inefficiencies and mis-reconstruction that generate artificial missing momentum. With this work, we propose a signal-agnostic strategy to reject ordinary jets and identify semivisible jets via anomaly detection techniques. A deep neural autoencoder network with jet substructure variables as input proves highly useful for analyzing anomalous jets. The study focuses on the semivisible jet signature; however, the technique can apply to any new physics model that predicts signatures with anomalous jets from non-SM particles. [ABSTRACT FROM AUTHOR]

Because of their potential low cost, bright light, and fast decay time, LuAG:Ce ceramic scintillators have attracted a broad interest in the high-energy physics community. One crucial issue for their application in future high-energy physics experiments is their radiation hardness against neutrons and protons expected at future hadron colliders. We report optical and scintillation performance of 1-mm LuAG:Ce ceramic samples doped with Mg2+ (and Ca2+) and their radiation damage induced by hadrons. While Mg2+ co-doping improves their light output, Ca2+ co-doping improves their fast to total (F/T) ratio. LuAG:Ce ceramic samples were irradiated at the Los Alamos Neutron Science Center (LANSCE), Los Alamos, NM, USA, by neutrons up to $6.7\times 10^{15}\,\,\text{n}_{\mathrm {eq}}$ /cm2 and by 24-GeV and 800-MeV protons at CERN PS-IRRAD up to $1.2\times 10^{15}$ p/cm2 and at LANSCE up to $2.3\times 10^{14}$ p/cm2, respectively. All samples show excellent radiation hardness with more than 90% of light after irradiation. The RIAC values induced by neutrons are found to be a factor of 2 smaller than lutetium–yttrium oxyorthosilicate (LYSO:Ce) crystals. The RIAC values induced by protons are also found a factor of 2 smaller than LYSO:Ce crystals in LuAG:Ce ceramic samples with good optical quality. Research and development will continue to develop LuAG:Ce scintillating ceramics with improved optical quality for future investigation. [ABSTRACT FROM AUTHOR]

The analytical expressions of the mixed QCD-EW corrections to on-shell Z boson inclusive production cross section at hadron colliders are presented, together with computational details. The results are given in terms of polylogarithmic functions and elliptic integrals. The impact on the prediction of the Z boson production total cross section is discussed, comparing different proton parton density sets. [ABSTRACT FROM AUTHOR]

One kind of particularly interesting pseudoscalar particles, called axion-like particles (ALPs), have rich physical phenomenology at high- and low-energy collider experiments. After discussing most of single production channels of ALP at electron-positron colliders, we investigate the possibility of detecting this kind of new particles through the W + W - fusion process e + e - → ν ¯ e ν e a (→ γ γ) at the CLIC. The 3 σ and 5 σ bounds on the ALP parameter space at the three energy stages of the CLIC are obtained. We find that the bounds given by the CLIC are complementary to the existing experiments exclusion regions. [ABSTRACT FROM AUTHOR]

We consider the associated production of a vector or Higgs boson with a jet in hadronic collisions. When the transverse momentum q T of the boson-jet system is much smaller than its invariant mass Q, the QCD perturbative expansion is affected by large logarithmic terms that must be resummed to all orders. We discuss the all-order resummation structure of the logarithmically enhanced contributions up to next-to-leading logarithmic accuracy. Resummation is performed at the differential level with respect to the kinematical variables of the boson-jet system. Soft-parton radiation produces azimuthal correlations that are fully accounted for in our framework. We present explicit analytical results for the resummation coefficients up to next-to-leading order and next-to-leading logarithmic accuracy, that include the exact dependence on the jet radius. [ABSTRACT FROM AUTHOR]

The potential of triphoton production to obtain limits on anomalous Higgs boson couplings at Hγγ and HZγ vertices is studied in Standard Model Effective Field Theory (EFT) framework for the post-LHC circular high-energy hadron colliders: High Luminosity-LHC (HL-LHC), High Energy LHC (HE-LHC) and Low Energy FCC (LE-FCC) which are designed with standard configurations of 14 TeV/3 ab-1, 27 TeV/15 ab-1 and 37.5 TeV/15 ab-1. Madgraph in which the effective Lagrangian of the SM EFT is implemented using FeynRules and UFO framework is used to generate both background and signal events. These events are then passed through Pythia 8 for parton showering and Delphes to include realistic detector effects. After optimizing cuts on kinematics of three photons as well as the reconstructed invariant mass of the two leading photons, invariant mass of three leading photon is used to obtain constraints on the Wilson coefficients of dimension-six operators. We report the result of two dimensional scan of ... and ... couplings at 95\% confidence level and compare with LHC results. Our obtained limits without systematic error on ... (...) are [-3.15;1.41]x10-2 ([02.12;2.12]x10-2), [-1.21;0.78]x10-2 ([-0.98;0.98]x10-2) and [-0.89;0.66]x10-2 ([-0.77;0.77]x10-2) for HL-LHC, HE-LHC and LE-FCC, respectively. [ABSTRACT FROM AUTHOR]

We examine current Large Hadron Collider constraints on some simple Z ′ models that significantly improve on Standard Model fits to b → s μ + μ - transition data. The models that we consider are the 'third family baryon number minus second family lepton number' ( B 3 - L 2 ) model and the 'third family hypercharge' model and variants. The constraints are applied on parameter regions of each model that fit the b → s μ + μ - transition data and come from high-mass Drell–Yan di-muons and measurements of Standard Model processes. This latter set of observables place particularly strong bounds upon the parameter space of the B 3 - L 2 model when the mass of the Z ′ boson is less than 300 GeV. [ABSTRACT FROM AUTHOR]

In this work we assess the potential of discovering new physics by searching for lepton-flavour-violating (LFV) decays of the Z boson, Z → ℓ i ℓ j , at the proposed circular e + e - colliders CEPC and FCC-ee. Both projects plan to run at the Z-pole as a "Tera Z factory", i.e., collecting O 10 12 Z decays. In order to discuss the discovery potential in a model-independent way, we revisit the LFV Z decays in the context of the Standard Model effective field theory and study the indirect constraints from LFV μ and τ decays on the operators that can induce Z → ℓ i ℓ j . We find that, while the Z → μ e rates are beyond the expected sensitivities, a Tera Z factory is promising for Z → τ ℓ decays, probing New Physics at the same level of future low-energy LFV observables. [ABSTRACT FROM AUTHOR]

We compute the two-loop QCD helicity amplitudes for the production of a Higgs boson in association with a bottom quark pair at a hadron collider. We take the approximations of leading colour and work in the five flavour scheme, where the bottom quarks are massless while the Yukawa coupling is non-zero. We extract analytic expressions from multiple numerical evaluations over finite fields and present the results in terms of an independent set of special functions that can be reliably evaluated over the full phase space. [ABSTRACT FROM AUTHOR]

We investigate different final state features in Mueller–Navelet jets events at hadron colliders. The focus lies on the average rapidity ratio between subsequent minijet emissions which has been investigated in previous works but now is modified to also incorporate the transverse momenta together with the rapidities of the emitted jets. We study the dependence of this observable on a lower transverse momentum veto which does affect the typical minijet multiplicity of the events under scrutiny. We find that this observable is stable when including higher order quantum corrections, also when collinear terms are resummed to all orders. [ABSTRACT FROM AUTHOR]

Hadron polarization control schemes for Spin Transparent (ST) synchrotrons are analyzed. The spin dynamics and beam polarization in such synchrotrons are controlled by spin navigators (SN) which are special small insertions of weak magnetic fields. An SN stabilizes the beam polarization and allows for setting any desirable spin orientation at an interaction point in the operational regime, including a frequent spin flip. We present a general approach to design of SNs. We distinguish different types of SNs, namely, those not causing closed orbit perturbation as well as those producing local and global orbit distortions. In the second case, the concept of the spin response function in an ST synchrotron is applied and expanded to reveal the effect of the SN strength enhancement by magnetic lattice of the synchrotron. We provide conceptual schemes for SN designs using longitudinal and transverse magnetic fields allowing for polarization control at low as well as high energies. We also develop the ST concept for ultra-high energies. This development may enable and stimulate interest in polarized beam experiments in possible polarized collider projects such as Large Hadron Collider (LHC), Future Circular Collider (FCC) and Super Proton Proton Collider (SPPC). [ABSTRACT FROM AUTHOR]

We explore models of new physics that can give rise to large (100% or more) enhancements to the rate of Higgs decay to Zγ while still being consistent with other measurements. We show that this is impossible in simple models with one additional multiplet and also in well motivated models such as the MSSM and folded SUSY. We do find models with several multiplets that carry electroweak charge where such an enhancement is possible, but they require destructive interference effects. We also show that kinematic measurements in Higgs decay to four leptons can be sensitive to such models. Finally we explore the sensitivity of four lepton measurements to supersymmetric models and find that while the measurement is difficult with the high luminosity LHC, it may be possible with a future high energy hadron collider. [ABSTRACT FROM AUTHOR]

We calculate, for the first time, the NNLO QCD corrections to identified heavy hadron production at hadron colliders. The calculation is based on a flexible numeric framework which allows the calculation of any distribution of a single identified heavy hadron plus jets and non-QCD particles. As a first application we provide NNLO QCD predictions for several differential distributions of B hadrons in t t ¯ events at the LHC. Among others, these predictions are needed for the precise determination of the top quark mass. The extension of our results to other processes, like open or associated B and charm production is straightforward. We also explore the prospects for extracting heavy flavor fragmentation functions from LHC data. [ABSTRACT FROM AUTHOR]

A high energy muon collider can provide new and complementary discovery potential to the LHC or future hadron colliders. Leptoquarks are a motivated class of exotic new physics models, with distinct production channels at hadron and lepton machines. We study a vector leptoquark model at a muon collider with s = 3, 14 TeV within a set of both UV and phenomenologically motivated flavor scenarios. We compute which production mechanism has the greatest reach for various values of the leptoquark mass and the coupling between leptoquark and Standard Model fermions. We find that we can probe leptoquark masses up to an order of magnitude beyond s with perturbative couplings. Additionally, we can also probe regions of parameter space unavailable to flavor experiments. In particular, all of the parameter space of interest to explain recent low-energy anomalies in B meson decays would be covered even by a s = 3 TeV collider. [ABSTRACT FROM AUTHOR]

We study the measurement of Higgs boson self-couplings through 2 → 3 vector boson scattering (VBS) processes in the framework of Standard Model effective field theory (SMEFT) at both proton and lepton colliders. The SMEFT contribution to the amplitude of the 2 → 3 VBS processes, taking WLWL → WLWLh and WLWL → hhh as examples, exhibits enhancement with the energy A BSM A SM ~ E 2 Λ 2 , which indicates the sensitivity of these processes to the related dimension-six operators in SMEFT. Simulation of the full processes at both hadron and lepton colliders with a variety of collision energies are performed to estimate the allowed region on c6 and c Φ 1 . Especially we find that, with the help of exclusively choosing longitudinal polarizations in the final states and suitable pT cuts, WWh process is as important as the more widely studied triple Higgs production (hhh) in the measurement of Higgs self-couplings. Our analysis indicates that these processes can play important roles in the measurement of Higgs self-couplings at future 100 TeV pp colliders and muon colliders. However, their cross sections are generally tiny at low energy machines, which makes them much more challenging to explore. [ABSTRACT FROM AUTHOR]

Experimental collaborations for the large hadron collider conducted various searches for supersymmetry. In the absence of signals, lower limits were put on sparticle masses but usually within frameworks with (over-)simplifications relative to the entire indications by supersymmetry models. For complementing current interpretations of experimental bounds, we introduce a 30-parameter version of the R-parity conserving Minimal Supersymmetric Standard Model (MSSM-30). Using a sample of the MSSM-30 which are in harmony with cold dark matter, flavor and precision electroweak constraints, we explicitly show the prospects for assessing neutralino candidate dark matter in contrast to future searches for supersymmetry. The MSSM-30-parameter regions that are beyond reach to dark matter direct detection experiments could be probed by future hadron–hadron colliders. [ABSTRACT FROM AUTHOR]

As a model independent approach to search for the signals of new physics (NP) beyond the Standard Model (SM), the SM effective field theory (SMEFT) draws a lot of attention recently. The energy scale of a process is an important parameter in the study of an EFT such as the SMEFT. However, for the processes at a hadron collider with neutrinos in the final states, the energy scales are difficult to reconstruct. In this paper, we study the energy scale of anomalous γγ → W+W− scattering in the vector boson scattering (VBS) process pp → jjℓ+ℓ−ν ν ¯ at the large hadron collider (LHC) using artificial neural networks (ANNs). We find that the ANN is a powerful tool to reconstruct the energy scale of γγ → W+W− scattering. The factors affecting the effects of ANNs are also studied. In addition, we make an attempt to interpret the ANN and arrive at an approximate formula which has only five fitting parameters and works much better than the approximation derived from kinematic analysis. With the help of ANN approach, the unitarity bound is applied as a cut on the energy scale of γγ → W+W− scattering, which is found to has a significant suppressive effect on signal events. The sensitivity of the process pp → jjℓ+ℓ−ν ν ¯ to anomalous γγWW couplings and the expected constraints on the coefficients at current and possible future LHC are also studied. [ABSTRACT FROM AUTHOR]

We provide a comprehensive discussion, together with a complete setup for simulations, relevant for the production of a single vector-like quark at hadron colliders. Our predictions include finite width effects, signal-background interference effects and next-to-leading order QCD corrections. We explicitly apply the framework to study the single production of a vector-like quark T with charge 2/3, but the same procedure can be used to analyse the single production of vector-like quarks with charge −4/3, −1/3, 2/3 and 5/3, when the vector-like quark interacts with the Standard Model quarks and electroweak bosons. Moreover, this procedure can be straightforwardly extended to include additional interactions with exotic particles. We provide quantitative results for representative benchmark scenarios characterised by the T mass and width, and we determine the role of the interference terms for a range of masses and widths of phenomenological significance. We additionally describe in detail, both analytically and numerically, a striking feature in the invariant mass distribution appearing only in the T → th channel. [ABSTRACT FROM AUTHOR]

Machine learning technology has the potential to dramatically optimise event generation and simulations. We continue to investigate the use of neural networks to approximate matrix elements for high-multiplicity scattering processes. We focus on the case of loop-induced diphoton production through gluon fusion, and develop a realistic simulation method that can be applied to hadron collider observables. Neural networks are trained using the one-loop amplitudes implemented in the NJet C++ library, and interfaced to the Sherpa Monte Carlo event generator, where we perform a detailed study for 2 → 3 and 2 → 4 scattering problems. We also consider how the trained networks perform when varying the kinematic cuts effecting the phase space and the reliability of the neural network simulations. [ABSTRACT FROM AUTHOR]

In the current analysis, we have reported the spectra of average transverse-sphericity as a function of multiplicity (𝑁𝑐ℎ) in 𝑝𝑝 collisions for primary charged particles (𝜋+,𝜋−,𝐾+,𝐾−,𝑝 and 𝑝̅) in mid pseudo-rapidity of |𝜂|<0.8 and in the kinematic transverse momentum range of 𝑝𝑇 >0.5 𝐺𝑒𝑉/𝑐 at √𝑠𝑁𝑁 = 0.9 and 7 𝑇𝑒𝑉. Two Monte Carlo event generators have been used for current analysis, and the predictions of the model are compared to the results coming from the ALICE experiment based at the Large Hadron Colli der (LHC). A detailed analysis has been carried out for three types of events (soft events, hard events and bulk events) categorized by the transverse momentum (𝑝𝑇) of the charged particles. It is observed that the predictions of model, underestimate ALICE data at larger values of 𝑁𝑐ℎ while at the low values of 𝑁𝑐ℎ, the calculated values of model are close to ALICE data. The predictions at 0.9 TeV explain ALICE data well. At large values of 𝑁𝑐ℎ, the models predominantly produce hard events as compared with those perceived from ALICE data. This variance can be observed in the bulk event class, as event generators produce more hard events, whereas experiment gives more soft events. At high multiplicity, the generators underestimate the production of isotropic events. The event generators favor the production of back to back jets (high-𝑝𝑇 jets, low <𝑆𝑇 >) and also generate large multiplicity events. [ABSTRACT FROM AUTHOR]

The observation of the decay of the Higgs boson to a bb pair in 2018 provided a confirmation of the Yukawa interaction and the first measurement of a Yukawa coupling to down-type quarks. The experimental challenges that the H → bb decay entails at hadron colliders can be addressed by studying the associated Higgs boson production with a vector boson V decaying leptonically. Following the observation, the main focus is now the study of the Higgs boson production cross section as a function of its transverse momentum (pT). These measurements are well motivated by a wide range of Beyond the Standard Model (BSM) theories predicting an enhancement of V H(H → bb) events at high transverse momentum with respect to the SM expectations. At such high energy regimes, the Higgs boson is highly Lorentz-boosted and the H → bb decay is reconstructed in the detector as a single object with a two-prong substructure, using novel techniques. The paper will illustrate the measurement of V H(H → bb) in the boosted regime performed inclusively, as well as in bins of the vector boson transverse momentum, for pVT ∈ [250, 400) GeV and pVT ∈ [400, ∞) GeV. Their interpretation using the Effective Field Theory (EFT) framework will also be discussed. The results are based on the full LHC Run 2 dataset collected by the ATLAS experiment, corresponding to an integrated luminosity of 139 fb-1. [ABSTRACT FROM AUTHOR]

The photoproduction of axion-like particles (ALPs) is investigated in electron–ion (EIC) and ultraperipheral heavy ion collisions (UPCs) considering the Primakoff production from a nucleus and effective Lagrangian for ALP coupling to photons. The model is employed to calculate the integrated cross section and event numbers as a function of the ALP mass and axion-photon coupling. Predictions are shown for EICs and proton–nucleus and nucleus–nucleus in UPCs at the large hadron collider. The results show that a considerable number of events can be produced on the planned experiments, specially for low ALP masses of few GeVs. Numerical calculations are provided in the kinematic coverage of the planned machines electron ion collider, large hadron electron collider and future circular collider. [ABSTRACT FROM AUTHOR]

In LHC Run 3, operating the ATLAS Pixel detector has been smooth, despite a typical number of interactions per bunch crossing of 62 in proton–proton collisions and after reaching fluence of O (1 0 15) 1 MeV n-eq cm−2. This contribution will detail the adjustments and improvements made to both the detector configuration and to the DAQ system respectively, necessary for keeping the performance of the ATLAS Pixel detector high as the operating conditions become more demanding, as well as results from radiation damage studies, their effect on operational parameters, and the subsequent outlook for the remainder of Run 3. [ABSTRACT FROM AUTHOR]

The paper provides an overview of the radiation protection challenges and the advanced simulation techniques used to study and plan complex interventions in radiation areas at CERN, particularly with regard to the Large Hadron Collider. The operational radiation protection aspects are supported by state of the art simulations by means of the FLUKA Monte Carlo code and estimates obtained via several tools, used within the CERN Radiation Protection group, such as ActiWiz, SESAME, and the Fluence Conversion Coefficients (FCC) method which extend the built-in FLUKA capabilities. The paper covers the general Radiation Protection principles and rules in force at CERN, the simulation tools/techniques used to fulfill operational tasks and predictive studies, and a set of case studies covering relevant applications at the Large Hadron Collider machine and experiments. • Advanced and reliable simulation tools are essential in modern Radiation Protection. • FLUKA is widely used at CERN for radiation protection studies at the LHC complex. • Simulation tools such as SESAME, FCC and ActiWiz extend FLUKA built-in capabilities. • RP studies of the upgrade of the LHC are mainly based on advanced simulation tools. • Real-case applications and examples are provided in the paper. [ABSTRACT FROM AUTHOR]

We calculate the complete set of two-loop leading-colour QCD helicity amplitudes for γγj-production at hadron colliders. Our results are presented in a compact, fully-analytical form. [ABSTRACT FROM AUTHOR]

We present the complete set of leading-color two-loop contributions required to obtain next-to-next-to-leading-order (NNLO) QCD corrections to three-jet production at hadron colliders. We obtain analytic expressions for a generating set of finite remainders, valid in the physical region for three-jet production. The analytic continuation of the known Euclidean-region results is determined from a small set of numerical evaluations of the amplitudes. We obtain analytic expressions that are suitable for phenomenological applications and we present a C++ library for their efficient and stable numerical evaluation. [ABSTRACT FROM AUTHOR]

We address the issues of clustering and non-global logarithms for jet shapes in the process of production of a Higgs/vector boson associated with a single hard jet at hadron colliders. We perform an analytical fixed-order calculation up to second order in the coupling as well as an all-orders estimation for the specific invariant mass distribution of the highest- p t jet, for various jet algorithms. Our results are derived in the eikonal (soft) limit and are valid up to next-to-leading logarithmic accuracy. We perform a matching of the resummed distribution to next-to-leading order results from MCFM and compare our findings with the outputs of the Monte Carlo event generators Pythia 8 and Herwig 7. After accounting for non-perturbative effects we compare our results with available experimental data from the CMS collaboration for the Z + jet production. We find good agreement over a wide range of the observable. [ABSTRACT FROM AUTHOR]

The increase of transverse segmentation is a trend in developments of modern calorimeter systems based on different technologies. The scintillator calorimeters assembled from SiPM-on-tile elements are now under development for future experiments at both lepton and hadron colliders. The study presents a validation of simulation of the response of a single SiPM-on-tile element. The experimental measurements are compared with the simulation using Geant4 framework followed by the digitization procedure that takes into account photodetector characteristics. The dependence on simulated optical properties is discussed and parameters are presented, which help to achieve a good agreement between data and simulation. [ABSTRACT FROM AUTHOR]

In this paper, we give a brief review of recent theoretical studies of double prompt J / ψ production at the FNAL Tevatron and the CERN LHC, to which both single- and double-parton-scattering processes contribute. In single parton scattering, we mainly present the results computed within the framework of non-relativistic quantum chromodynamics factorization combined with one of the two approaches to describe the parton inside the (anti)proton, the collinear parton model and the parton Reggeization approach. The contributions from double parton scattering calculated with different values of σ eff are also discussed. We conclude that, in double prompt J / ψ hadroproduction, there remain some differences between theoretical predictions and experimental measurements. [ABSTRACT FROM AUTHOR]

In the framework of the U.S. Magnet Development Program (MDP), Fermilab has developed and tested a high-field Nb3Sn dipole demonstrator MDPCT1 for a post-LHC Hadron Collider. The magnet was first assembled with a lower coil pre-load to minimize the risk of coil damage during assembly and test. In the first test the magnet reached its test goal producing a world record field of 14.1 T at 4.5 K. Next the magnet was reassembled with nominal pre-load to achieve its design field limit of 15 T. This paper describes the details of MDPCT1 inspection, design modifications and reassembly. The magnet quench performance, including training, ramp rate and temperature dependences in the temperature range of 1.9-4.5 K, is presented and discussed. [ABSTRACT FROM AUTHOR]

We discuss cross sections for tW production in proton-proton collisions at the LHC and at higher-energy colliders with energies of up to 100 TeV. We find that, remarkably, the soft-gluon corrections are numerically dominant even at very high collider energies. We present results with soft-gluon corrections at approximate NNLO and approximate N3LO matched to complete NLO results. These higher-order corrections are large and need to be included for better theoretical accuracy and smaller scale dependence. Total cross sections as well as top-quark and W-boson transverse-momentum and rapidity distributions are presented using various recent sets of parton distribution functions. [ABSTRACT FROM AUTHOR]

Using an effective field theory approach for higher-spin fields, we derive the interactions of colour singlet and electrically neutral particles with a spin higher than unity, concentrating on the spin-3/2, spin-2, spin-5/2 and spin-3 cases. We compute the decay rates and production cross sections in the main channels for spin-3/2 and spin-2 states at both electron-positron and hadron colliders, and identify the most promising novel experimental signatures for discovering such particles at the LHC. The discussion is qualitatively extended to the spin-5/2 and spin-3 cases. Higher-spin particles exhibit a rich phenomenology and have signatures that often resemble the ones of supersymmetric and extra-dimensional theories. To enable further studies of higher-spin particles at collider and beyond, we collect the relevant Feynman rules and other technical details. [ABSTRACT FROM AUTHOR]

Displaced vertices at colliders, arising from the production and decay of long-lived particles, probe dark matter candidates produced via freeze-in. If one assumes a standard cosmological history, these decays happen inside the detector only if the dark matter is very light because of the relic density constraint. Here, we argue how displaced events could very well point to freeze-in within a non-standard early universe history. Focusing on the cosmology of inflationary reheating, we explore the interplay between the reheating temperature and collider signatures for minimal freeze-in scenarios. Observing displaced events at the LHC would allow to set an upper bound on the reheating temperature and, in general, to gather indirect information on the early history of the universe. [ABSTRACT FROM AUTHOR]