We demonstrate that neural networks can be used to improve search strategies, over existing strategies, in LHC searches for light electroweak-charged scalars that decay to a muon and a heavy invisible fermion. We propose a new search involving a neural network discriminator as a final cut and show that different signal regions can be defined using networks trained on different subsets of signal samples (distinguishing low-mass and high-mass regions). We also present a workflow using publicly-available analysis tools, that can lead, from background and signal simulation, to network training, through to finding projections for limits using an analysis and libraries to interface network and recasting tools. We provide an estimate of the sensitivity of our search from Run 2 LHC data, and projections for higher luminosities, showing a clear advantage over previous methods.

South Africa

Alan Cornell

France

Benjamin Fuks

Mark Goodsell

Anele Ncube

Improving smuon searches with neural networks

The most recent searches by the ATLAS and CMS Collaborations in final states with soft leptons and missing transverse energy show mild excesses predominantly associated with dilepton invariant masses of about  $$10{-}20$$  <math> <mrow> <mn>10</mn> <mo>-</mo> <mn>20</mn> </mrow> </math>   GeV, which can result from decays of electroweakinos that are heavier than the lightest neutralino by  $$\mathcal {O}(10)$$  <math> <mrow> <mi>O</mi> <mo>(</mo> <mn>10</mn> <mo>)</mo> </mrow> </math>   GeV. On the other hand, these analyses are insensitive to electroweakino mass splittings smaller than about 5 GeV. In previous work, we demonstrated that while recent searches in the monojet channel can exclude some of the smallest  $$\mathcal {O}(1)$$  <math> <mrow> <mi>O</mi> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </math>   GeV mass splitting configurations for electroweakinos, they also exhibit excesses that can overlap with the soft-lepton excesses in certain models, including a simplified scenario with pure higgsinos. In this work we dive deeper into these excesses, studying the analyses in detail and exploring an array of models that go beyond the simplified scenarios considered by the experimental collaborations. We show that, in the Minimal Supersymmetric Standard Model, the overlapping excesses are not unique to the pure-higgsino limit, instead persisting in realistic parameter space featuring a bino-like lightest supersymmetric particle with some wino admixture. On the other hand, for the Next-to-Minimal Supersymmetric Standard Model with a singlino-like lightest supersymmetric particle and higgsino-like next-to-lightest supersymmetric particle(s), the excess in the two-lepton channel fits rather well with the parameter space predicting the correct relic abundance through freeze out, but the monojet fit is much poorer. Interestingly, the excesses either do not overlap or do not exist at all for two non-supersymmetric models seemingly capable of producing the correct final states.

Diyar Agin

Taylor Murphy

Seeking a coherent explanation of LHC excesses for compressed spectra

We introduce a phenomenological model for a string-derived  $$Z^\prime $$  <math> <msup> <mi>Z</mi> <mo>′</mo> </msup> </math>   scenario, and study its predictions for the mass of the W boson. In the process, we compare it to collider constraints for both pair-produced particles, Higgs boson properties, and  $$Z^\prime $$  <math> <msup> <mi>Z</mi> <mo>′</mo> </msup> </math>   searches. We also describe the implementation of new tools in the scanning code BSMArt.

United Kingdom

Alon Faraggi

$$M_W$$  <math> <msub> <mi>M</mi> <mi>W</mi> </msub> </math>   in string derived Z $$^\prime $$  <math> <msup> <mrow></mrow> <mo>′</mo> </msup> </math>   models

We present an update of the Universal FeynRules Output model format, commonly known as the UFO format, that is used by several automated matrix-element generators and high-energy physics software. We detail different features that have been proposed as extensions of the initial format during the last ten years, and collect them in the current second version of the model format that we coin the Universal Feynman Output format. Following the initial philosophy of the UFO, they consist of flexible and modular additions to address particle decays, custom propagators, form factors, the renormalisation group running of parameters and masses, and higher-order quantum corrections.

Luc Darmé

Belgium

Céline Degrande

Germany

Claude Duhr

Gudrun Heinrich

Switzerland

Valentin Hirschi

United States

Stefan Höche

Marius Höfer

Joshua Isaacson

Olivier Mattelaer

Thorsten Ohl

Italy

Davide Pagani

Jürgen Reuter

Peter Richardson

Steffen Schumann

Hua-Sheng Shao

Frank Siegert

Marco Zaro

UFO 2.0: the ‘Universal Feynman Output’ format

Active learning (AL) has interesting features for parameter scans of new models. We show on a variety of models that AL scans bring large efficiency gains to the traditionally tedious work of finding boundaries for BSM models. In the MSSM, this approach produces more accurate bounds. In light of our prior publication, we further refine the exploration of the parameter space of the SMSQQ model, and update the maximum mass of a dark matter singlet to 48.4 TeV. Finally we show that this technique is especially useful in more complex models like the MDGSSM.

Ari Joury

Active learning BSM parameter spaces

We investigate the conditions for alignment in Dirac Gaugino models with minimal matter content. This leads to several scenarios, including an aligned Dirac Gaugino NMSSM that allows a light singlet scalar. We then investigate the compatibility of minimal Dirac Gaugino models with an enhanced W boson mass, using a new precise computation of the quantum corrections included in the code SARAH 4.15.0.

Karim Benakli

Wenqi Ke

Pietro Slavich

W boson mass in minimal Dirac gaugino scenarios

We address the prediction for the mass of the SM-like Higgs boson in NMSSM scenarios where all BSM particles, including the singlets, have masses at the TeV scale. We provide a full one-loop computation of the matching condition for the quartic Higgs coupling in the NMSSM, supplemented with the two-loop contributions that involve the strong gauge coupling. We discuss the impact of the one- and two-loop corrections that are specific to the NMSSM on the prediction for the Higgs mass, and propose a method to estimate of the uncertainty associated with the uncomputed higher-order terms. Finally, we illustrate how the measured value of the Higgs mass can be used to constrain some yet-unmeasured parameters of the NMSSM.

CERN

Emanuele Bagnaschi

Higgs-mass prediction in the NMSSM with heavy BSM particles

We present an extension of the simplified fast detector simulator of MadAnalysis 5 – the SFS framework – with methods making it suitable for the treatment of long-lived particles of any kind. This allows users to make use of intuitive Python commands and straightforward C++ methods to introduce detector effects relevant for long-lived particles, and to implement selection cuts and plots related to their properties. In particular, the impact of the magnetic field inside a typical high-energy physics detector on the trajectories of any charged object can now be easily simulated. As an illustration of the capabilities of this new development, we implement three existing LHC analyses dedicated to long-lived objects, namely a CMS run 2 search for displaced leptons in the  $$e\mu $$  <math> <mrow> <mi>e</mi> <mi>μ</mi> </mrow> </math>   channel (CMS-EXO-16-022), the full run 2 CMS search for disappearing track signatures (CMS-EXO-19-010), and the partial run 2 ATLAS search for displaced vertices featuring a pair of oppositely charged leptons (ATLAS-SUSY-2017-04). We document the careful validation of all MadAnalysis 5 SFS implementations of these analyses, which are publicly available as entries in the MadAnalysis 5 Public Analysis Database and its associated dataverse.

Jack Araz

Manuel Utsch

Recasting LHC searches for long-lived particles with MadAnalysis 5

In the Next-to-Minimal Supersymmetric Standard Model there is a strong correlation between the mass terms corresponding to the singlet Higgs and the singlino interaction states, both of which are proportional to the parameter  $$\kappa $$  <math> <mi>κ</mi> </math>  . If this parameter is complex, explicit CP-violation occurs in the Higgs as well as the neutralino sectors of the model at the tree level, unlike in the minimal scenario. A small magnitude of  $$\kappa $$  <math> <mi>κ</mi> </math>   typically yields a  $${{\mathcal {O}}}$$  <math> <mi>O</mi> </math>  (10) GeV lightest neutralino with a dominant singlino component. In such a scenario, the phase of  $$\kappa $$  <math> <mi>κ</mi> </math>  , beside modifying the properties of the five Higgs bosons, can also have a crucial impact on the phenomenology of the neutralino dark matter. In this study we perform a first investigation of this impact on the relic abundance of the dark matter solutions with sub-100 GeV masses, obtained for parameter space configurations of the model that are consistent with a variety of current experimental data.

China

Waqas Ahmed

Rwanda

Shoaib Munir

Dark matter in the CP-violating NMSSM

We describe a new code and approach using particle-level information to recast the recent CMS disappearing track searches including all Run 2 data. Notably, the simulation relies on knowledge of the detector geometry, and we also include the simulation of pileup events directly rather than as an efficiency function. We validate it against provided acceptances and cutflows, and use it in combination with heavy stable charged particle searches to place limits on winos with any proper decay length above a centimetre. We also provide limits for a simple model of a charged scalar that is only produced in pairs, that decays to electrons plus an invisible fermion.

India

Lakshmi Priya

Long dead winos