A series of far-detector programs have been proposed for operation at various interaction points of the large hadron collider during the upcoming runs. Investigating the potential and complementarity of these experiments for new-physics searches goes through the estimation of their sensitivity to specific long-lived particle models. Here, we present an integrated numerical tool written in the C++ language and called Displaced Decay Counter, which we have created to this end and which can be used in association with MadGraph5, Pythia8, or any other state-of-the-art Monte-Carlo collider simulation tool. Several far-detector models have been implemented within the program, accounting for the geometry and integrated luminosity of projected detectors. Additional or more accurate designs can be easily constructed through a dedicated interface. The functionality of this tool is exemplified through the discussion of several benchmark scenarios, which we consider for the validation of the implemented detector models.

We present updated LHC limits on the minimal universal extra dimensions (MUEDs) model from the Run 2 searches. We scan the parameter space against a number of searches implemented in the public code CheckMATE and derive up-to-date limits on the MUED parameter space from 13[Formula: see text]TeV searches. The strongest constraints come from a search dedicated to squarks and gluinos with one isolated lepton, jets and missing transverse energy. In the procedure, we take into account initial state radiation and stress its importance in the MUED searches, which is not always appreciated.

We investigate the possibility that right-handed (RH) sneutrinos and gravitinos can coexist and explain the dark matter (DM) problem. We compare extensions of the minimal supersymmetric standard model (MSSM) and the next-to-MSSM (NMSSM) adding RH neutrinos superfields, with special emphasis on the latter. If the gravitino is the lightest supersymmetric particle (LSP) and the RH sneutrino the next-to-LSP (NLSP), the heavier particle decays to the former plus left-handed (LH) neutrinos through the mixing between the scalar partners of the LH and RH neutrinos. However, the interaction is suppressed by the Planck mass, and if the LH-RH sneutrino mixing parameter is small, << O(10-2), a long-lived RH sneutrino NLSP is possible even surpassing the age of the Universe. As a byproduct, the NLSP to LSP decay produces monochromatic neutrinos in the ballpark of current and planned neutrino telescopes like Super-Kamiokande, IceCube and Antares that we use to set constraints and show prospects of detection. In the NMSSM+RHN, assuming a gluino mass parameter M3 = 3 TeV we found the following lower limits for the gravitino mass m3/2 >= 1-600 GeV and the reheating temperature TR >= 105-3 x 107 GeV, for m nu similar to R similar to 10-800 GeV. If we take M3 = 10 TeV, then the limits on TR are relaxed by one order of magnitude.

A bstract In this paper we explore the possibility of explaining the muon g − 2 anomaly in various types of supersymmetric extensions of the Standard Model. In particular, we investigate and compare the phenomenological constraints in the MSSM with stable neutralino and the other types of scenarios where the neutralino is unstable. For the latter case we study the Gauge Mediated SUSY Breaking (GMSB) scenario with very light gravitino and the UDD -type R-Parity Violating (RPV) scenario. In the MSSM with stable neutralino, the parameter region favoured by the ( g − 2) μ is strongly constrained by the neutralino relic abundance and the dark matter direct detection experiments, as well as by the LHC searches in the lepton plus missing transverse energy channel. On the other hand, the scenarios without stable neutralino are free from the dark matter constraints, while the LHC constraints depends strongly on the decay of the neutralino. We find that in GMSB the entire parameter region favoured by the muon g − 2 is already excluded if the Next Lightest SUSY Particle (NLSP) is the neutralino. In the GMSB scenario with a stau NSLP and in the RPV scenario, LHC constraints are weaker than the stable neutralino case and a larger region of parameter space is available to fit the ( g − 2) μ anomaly.

In this paper we investigate the (g−2)μ discrepancy in the context of the R-parity conserving next-to-minimal supersymmetric Standard Model plus right-handed neutrinos superfields. The model has the ability to reproduce neutrino physics data and includes the interesting possibility to have the right-handed sneutrino as the lightest supersymmetric particle and a viable dark matter candidate. Since right-handed sneutrinos are singlets, no new contributions for δaμ with respect to the MSSM and NMSSM are present. However, the possibility to have the right-handed sneutrino as the lightest supersymmetric particle opens new ways to escape Large Hadron Collider and direct detection constraints. In particular, we find that dark matter masses within 10≲mν˜R≲600 GeV are fully compatible with current experimental constraints. Remarkably, not only spectra with light sleptons are needed, but we obtain solutions with mμ˜≳600 GeV in the entire dark matter mass range that could be probed by new (g−2)μ data in the near future. In addition, dark matter direct detection experiments will be able to explore a sizable portion of the allowed parameter space with mν˜R≲300 GeV, while indirect detection experiments will be able to probe a much smaller fraction within 200≲mν˜R≲350 GeV.

We present the updated LHC limits on the minimal universal extra dimensions (MUED) model from the Run 2 searches. We scan the parameter space against a large number of searches implemented in the public code \textsc{CheckMATE} and show that large uncertainties in the limits exist when modelling using parton showers alone due to differences in the evolution starting scale, especially in the compressed spectra. This motivates us to incorporate matching, thus deriving the most up-to-date limits on the MUED parameter space from 13 TeV searches.

Long-lived particles have become a new frontier in the exploration of physics beyond the Standard Model. In this paper, we present the implementation of four types of long-lived particle searches, viz. displaced leptons, disappearing track, displaced vertex with either muons or with missing transverse energy, and heavy charged tracks. These four categories cover the signatures of a large range of physics models. We illustrate their potential for exclusion and discuss their mutual overlaps in mass-lifetime space for two simple phenomenological models involving either a U(1)-charged or a coloured scalar.

Purpose: To determine the usefulness of measuring the tortuosity of retinal arteries using smartphone fundus photographs to quantify plus disease in retinopathy of prematurity (ROP) patients. Methods: Digital fundus photographs were taken with a smartphone of 116 eyes involving 58 premature infants. The tortuosity of retinal arteries named as the tortuosity index (TI) was measured with Image J software. Patients were classified into the treated and control groups and the TIs of the two groups were compared. A receiver operating characteristic curve was constructed and areas under the curve (AUC) were calculated to quantify the diagnostic utility of TI. Results: Fundus photographs of 98 eyes of 50 premature infants were analyzed; 38 eyes of 20 infants were the treated group and 60 eyes of 30 infants were the control group. The TI was 1.231 +/- 0.156 in the treated group before treatment, which was significantly larger than 1.062 +/- 0.019 in the control group. After treatment of the treated group, the TI was 1.100 +/- 0.093, which was significantly smaller than before treatment. The AUC was 0.926, and using a cut-off value of 1.095, the sensitivity and specificity of TIs for requiring treatment were 85.1% and 95.5%, respectively. Conclusions: The tortuosity of retinal arteries was measured by analyzing smartphone fundus photographs to quantify plus disease in ROP patients. This method may be helpful for screening, follow-up, and treatment decisions for ROP patients.

We test the impact of the ATLAS and CMS multilepton searches performed at the LHC with 8 as well as 13 TeV center-of-mass energy (using only the pre-2018 results) on the chargino and neutralino sector of the next-to-minimal supersymmetric Standard Model (NMSSM). Our purpose consists in analyzing the actual reach of these searches for a full model and in emphasizing effects beyond the minimal supersymmetric Standard Model (MSSM) that affect the performance of current (MSSM-inspired) electroweakino searches. To this end, we consider several scenarios characterizing specific features of the NMSSM electroweakino sector. We then perform a detailed collider study, generating Monte Carlo events through pythia and testing against current LHC constraints implemented in the public tool checkmate. We find e.g., that supersymmetric decay chains involving intermediate singlino or Higgs-singlet states can modify the naive MSSM-like picture of the constraints by inducing final states with softer or less easily identifiable SM particles---reversely, a compressed configuration with singlino next-to-lightest supersymmetric particle occasionally induces final states that are rich with photons, which could provide complementary search channels.

We consider dark sectors with spontaneously broken gauge symmetries, where cascade decays of the dark sector fields naturally produce multi-Higgs boson final states along with dark matter. Our study focuses on two and three Higgs boson final states with missing energy using a multivariate analysis with boosted decision trees. We find that the di-Higgs boson channel is quite promising for the (b) over barb + gamma gamma and (b) over barb + (l) over barl decay modes. The tri-Higgs boson final state with missing energy, on the other hand, appears to be beyond the reach of the LHC in analogous channels. This may change when fully hadronic Higgs boson decays are considered.

Novel homoleptic cyclometalated Ir(III) complexes are designed to improve their emission dipole orientations in the emitting layer of blue phosphorescent organic light emitting devices. Biphenyl group is introduced into the imidazole of cyclometalated Ir(III) complexes to simultaneously achieve enhanced efficiency and operation lifetime, resulting in one of the best device performances of single‐stacked organic light emitting diodes with 91% emission dipole orientation, 26.3% maximum external quantum efficiency (maximally calculated as 41%), and 169 h lifetime at 1000 cd m −2 (LT80), color coordinate (0.17, 0.30). To elucidate the physical origin of this significant improvements, the orientational and positional distributions of the homoleptic dopants are analyzed with consideration on intermolecular interactions through atomistic modeling of the emitting layer. With the findings, the phosphorescent dopants could be designed in the future to achieve enhanced performance.

We present a deep learning solution to the prediction of particle production cross sections over a complicated, high-dimensional parameter space. We demonstrate the applicability by providing state-of-the-art predictions for the production of charginos and neutralinos at the Large Hadron Collider (LHC) at the next-to-leading order in the phenomenological MSSM-19 and explicitly demonstrate the performance for pp→χ̃^+_1χ̃^-_1, χ̃^0_2χ̃^0_2 and χ̃^0_2χ̃^± _1 as a proof of concept which will be extended to all SUSY electroweak pairs. We obtain errors that are lower than the uncertainty from scale and parton distribution functions with mean absolute percentage errors of well below 0.5 % allowing a safe inference at the next-to-leading order with inference times that improve the Monte Carlo integration procedures that have been available so far by a factor of 𝒪(10^7) from 𝒪(min) to 𝒪(μs) per evaluation.

We investigate the discovery potential of a Stealth SUSY scenario involving squark decays by reconstructing the lightest neutralino decay products using a large-radius jet containing a high transverse momentum photon. Requirements on the event topology, such as photon and large-radius jet multiplicity result in less background than signal. We also estimated the sensitivity of our analysis and found that it has a better exclusion potential compared to the strongest existing search for the specific benchmark points considered here.

Several ideas exist on how the stringent mass limits from LHC on new colored particles can be avoided. One idea are the so-called “stealth” scenarios in which missing transversal energy (ET) is avoided due a peculiar mass configuration. It is usually assumed that the cascade decay of the dominantly produced colored particle finishes in a two-body decay, where this mass configuration leads to a very small amount of ET. We discuss here the potential impact of other decay channels, either loop-induced or via off-shell mediators. It is shown that those channels already become important even for moderate branching ratios of 10%. Larger branching ratios, in particular, into a photon can completely wash out all benefits of the stealth setup. We discuss this in a model-independent form, but also at the simplest supersymmetry stealth scenario which can be realized in the next-to-minimal supersymmetric standard model.

We update the bounds on R-parity violating supersymmetry originating from meson oscillations in the B d/ s 0 and K0 systems. To this end, we explicitly calculate all corresponding contributions from R-parity violating operators at the one-loop level, thereby completing and correcting existing calculations. We apply our results to the derivation of bounds on R-parity violating couplings, based on up-to-date experimental measurements. In addition, we consider the possibility of cancellations among flavor-changing contributions of various origins, e.g. from multiple R-parity violating couplings or R-parity conserving soft terms. Destructive interferences among new-physics contributions could then open phenomenologically allowed regions, for values of the parameters that are naively excluded when the parameters are varied individually.

The interpretation of Large Hadron Collider (LHC) data in the framework of Beyond the Standard Model (BSM) theories is hampered by the need to run computationally expensive event generators and detector simulators. Performing statistically convergent scans of high-dimensional BSM theories is consequently challenging, and in practice unfeasible for very high-dimensional BSM theories. We present here a new machine learning method that accelerates the interpretation of LHC data, by learning the relationship between BSM theory parameters and data. As a proof-of-concept, we demonstrate that this technique accurately predicts natural SUSY signal events in two signal regions at the High Luminosity LHC, up to four orders of magnitude faster than standard techniques. The new approach makes it possible to rapidly and accurately reconstruct the theory parameters of complex BSM theories, should an excess in the data be discovered at the LHC.

Using the latest LHC data, we analyse and compare the lower limits on the masses of gluinos and the lightest stop in two natural supersymmetric motivated scenarios: one with a neutralino being the lightest supersymmetric particle (LSP) and the other one with gravitino as the LSP and neutralino as the next-to-lightest supersymmetric particle. In the second case our analysis applies to neutralinos promptly decaying to very light gravitinos, which are of cosmological interest, and are generic for low, of order $$ \mathcal{O} $$ (100) TeV, messenger scale in gauge mediation models. We find that the lower bounds on the gluino and the lightest stop masses are stronger for the gravitino LSP scenarios due to the extra handle from the decay products of neutralinos. Generally, in contrast to the neutralino LSP case the limits now extend to a region of compressed spectrum. In bino scenarios the highest excluded stop mass increases from 1000 GeV to almost 1400 GeV. Additionally, in the higgsino-like NLSP scenario the higgsinos below 650 GeV are universally excluded and the stop mass limit is $$ {m}_{\tilde{t}} $$> 1150 GeV, whereas there is no limit on stops in the higgsino LSP model for $$ {m}_{\tilde{h}} $$ = 650 GeV. Nevertheless, we find that the low messenger scale still ameliorates the fine tuning in the electroweak potential.

We consider pair-production of electroweakinos promptly decaying to light gravitinos in general gauge mediation scenarios within the minimal supersymmetric standard model. Typically the presence of photons and missing transverse momentum is the key signature for this kind of scenarios. We highlight where LHC analyses which have originally been designed to probe different scenarios provide complementary constraints with respect to the dedicated searches and we present the constraints on the parameter space.

We analyze the constraints on models of WIMP dark matter that can be derived from upper bounds on the "monojet" cross section at the LHC. These constraints were originally interpreted in the context of an effective field theory (EFT) where the Standard Model is extended by a dimension-6 operator whose coefficient is 1/Lambda(2). We show that combining the 8 TeV data of the ATLAS and CMS collaborations improves the bounds only slightly. We then analyze this final state in the context of simplified models with an s-channel mediator. We show that if the decay width of the mediator is small, these simplified models can be accurately modeled by the effective field theory only if the mediator mass is above 5 TeV. Finally, we point out that even if the EFT accurately describes the O(Lambda(-2)) contributions to the matrix element, for values of. near the current bound it receives significant contributions of order Lambda(-4); in the context of simplified models, these correspond to diagrams where two mediators are exchanged. This observation challenges the internal consistency of the EFT description since dimension-8 operators, which would also contribute to O(Lambda(-4)) to the matrix element, are not included.

One of the most promising strategies to identify the nature of dark matter consists in the search for new particles at accelerators and with so-called direct detection experiments. Working within the framework of simplified models, and making use of machine learning tools to speed up statistical inference, we address the question of what we can learn about dark matter from a detection at the LHC and a forthcoming direct detection experiment. We show that with a combination of accelerator and direct detection data, it is possible to identify newly discovered particles as dark matter, by reconstructing their relic density assuming they are weakly interacting massive particles (WIMPs) thermally produced in the early Universe, and demonstrating that it is consistent with the measured dark matter abundance. An inconsistency between these two quantities would instead point either towards additional physics in the dark sector, or towards a non-standard cosmology, with a thermal history substantially different from that of the standard cosmological model.