High Energy Physics Experiment

Differential cross sections have been extracted from exclusive and kinematically complete high-statistics measurements of quasifree polarizedn⃗ pscattering performed in the energy region of thed∗(2380)dibaryon resonance covering the the range of beam energiesTn= 0.98 - 1.29 GeV (s√= 2.32 - 2.44 GeV). The experiment was carried out with the WASA-at-COSY setup having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree processdp→np+pspectator. That way thenpdifferential cross sectionσ(Θ)was measured over a large angular range. The obtained angular distributions complement the corresponding analyzing powerAy(Θ)measurements published previously. A SAID partial-wave analysis incorporating the new data strengthens the finding of a resonance pole in the coupled3D3−3G3waves.

The reactionγp??K+?(1520)using photoproduction data from the CLASg12experiment at Jefferson Lab is studied. The decay of?(1520)into two exclusive channels,Σ+???andΣ???+, is studied from the detectedK+,?+, and???particles. A good agreement is established for the?(1520)differential cross sections with the previous CLAS measurements. The differential cross sections as a function of CM angle are extended to higher photon energies. Newly added are the differential cross sections as a function of invariant 4-momentum transfert, which is the natural variable to use for a theoretical model based on a Regge-exchange reaction mechanism. No newN??resonances decaying into theK+?(1520)final state are found.

Differential cross-section measurements are presented for the electroweak production of two jets in association with aZboson. These measurements are sensitive to the vector-boson fusion production mechanism and provide a fundamental test of the gauge structure of the Standard Model. The analysis is performed using proton-proton collision data collected by ATLAS ats√=13 TeV and with an integrated luminosity of 139 fb−1. The differential cross-sections are measured in theZ→ℓ+ℓ−decay channel (ℓ=e,μ) as a function of four observables: the dijet invariant mass, the rapidity interval spanned by the two jets, the signed azimuthal angle between the two jets, and the transverse momentum of the dilepton pair. The data are corrected for the effects of detector inefficiency and resolution and are sufficiently precise to distinguish between different state-of-the-art theoretical predictions calculated using Powheg+Pythia8, Herwig7+Vbfnlo and Sherpa 2.2. The differential cross-sections are used to search for anomalous weak-boson self-interactions using a dimension-six effective field theory. The differential cross-section as a function of the signed azimuthal angle between the two jets is found to be particularly sensitive to the interference between the Standard Model and dimension-six scattering amplitudes and provides a direct test of charge-conjugation and parity invariance in the weak-boson self-interactions.

The classic searches for supersymmetry have not given any strong indication for new physics. Therefore CMS is designing dedicated searches to target the more difficult and specific supersymmetry scenarios. This contribution present three such recent searches based on 13 TeV proton-proton collisions recorded with the CMS detector in 2016, 2017 and 2018: a search for heavy gluinos cascading via heavy next-to-lightest neutralino in final states with boosted Z bosons and missing transverse momentum; a search for compressed supersymmetry in final states with soft taus; and a search for compressed, long-lived charginos in hadronic final states with disappearing tracks.

This Letter describes a search for resonant new physics using a machine-learning anomaly detection procedure that does not rely on a signal model hypothesis. Weakly supervised learning is used to train classifiers directly on data to enhance potential signals. The targeted topology is dijet events and the features used for machine learning are the masses of the two jets. The resulting analysis is essentially a three-dimensional searchA→BC, formA∼O(TeV),mB,mC∼O(100 GeV)andB,Care reconstructed as large-radius jets, without paying a penalty associated with a large trials factor in the scan of the masses of the two jets. The full Run 2s√=13TeVppcollision data set of 139 fb−1recorded by the ATLAS detector at the Large Hadron Collider is used for the search. There is no significant evidence of a localized excess in the dijet invariant mass spectrum between 1.8 and 8.2 TeV. Cross-section limits for narrow-widthA,B, andCparticles vary withmA,mB, andmC. For example, whenmA=3TeV andmB≳200GeV, a production cross section between 1 and 5 fb is excluded at 95% confidence level, depending onmC. For certain masses, these limits are up to 10 times more sensitive than those obtained by the inclusive dijet search.

Since the discovery of CP violation more than 5 decades ago, this phenomenon is still attracting a lot of interest. Among the many fascinating aspects of this subject, this review is dedicated to direct CP violation in non-leptonic decays. The advances within the last decade have been enormous, driven by the increasingly large samples of b- and c-hadron decays, and have led to very interesting results such as large CP asymmetries in charmless B decays and the observation of direct CP violation in the charm sector. We address the quest for understanding the origin of strong phases, the importance of final state interactions and the relation with CPT symmetry, and different approaches to measure direct CP violation in these decays. The main experimental results and their implications are then discussed.

In these proceedings we present the latest results from ALICE on direct photon and light neutral meson production in p−Pb and Pb−Pb collisions. The direct photon excess ratioRγin different charged particle multiplicity classes of p−Pb collisions atsNN−−−√=5.02TeVis shown. In addition, we present the direct photon elliptic flow coefficientv2in central and semicentral events of Pb−Pb collisions atsNN−−−√=2.76TeV. An outlook on ongoing and future measurements is given.

The interaction rate of hypothesised dark matter particles in an Earth-bound detector is expected to undergo an annual modulation due to the planet's orbital motion. The DAMA experiment has observed such a modulation with high significance in an array of scintillating NaI(Tl) crystals. This claim is still unverified inasmuch as the other experiments involved in this research use different dark matter targets and cannot be compared with DAMA in a model-independent way. The SABRE experiment seeks to provide a much-needed model-independent test by developing highly pure NaI(Tl) crystal detectors with very low radioactivity and deploying them into an active veto detector that can reject key backgrounds in a dark matter measurement. The final layout of SABRE will consist of a pair of twin detectors at LNGS (Laboratori Nazionali del Gran Sasso, Italy) and SUPL (Stawell Underground Physics Laboratory, Australia). The combined analysis of data sets from the two hemispheres will allow to identify any terrestrial contribution to the modulating signal. This article gives an overview of the detector design together with the results of Monte Carlo simulations and of the status of SABRE proof-of-principle activities at LNGS.

NEWAGE is a direction-sensitive dark matter search using a low-pressure gaseous time projection chamber. A low alpha-ray emission rate micro pixel chamber had been developed in order to reduce background for dark matter search. We conducted the dark matter search at the Kamioka Observatory in 2018. The total live time was 107.6 days corresponding to an exposure of 1.1 kg??days. Two events remained in the energy region of 50-60 keV which was consistent with 2.5 events of the expected background. A directional analysis was carried out and no significant forward-backward asymmetry derived from the WIMP-nucleus elastic scatterings was found. Thus a 90% confidence level upper limit on Spin-Dependent WIMP-proton cross section of 50 pb for a WIMP mass of 100 GeV/c2 was derived. This limit is the most stringent yet obtained from direction-sensitive dark matter search experiments.

MINERvA reports inclusive charged-current cross sections for muon neutrinos on hydrocarbon in the NuMI beamline. We measured the double-differential cross section in terms of the longitudinal and transverse muon momenta, as well as the single-differential cross sections in those variables. The data used in this analysis correspond to an exposure of3.34×1020protons on target with a peak neutrino energy of approximately 3.5 GeV. Measurements are compared to the GENIE, NuWro and GiBUU neutrino cross-section predictions, as well as a version of GENIE modified to produce better agreement with prior exclusive MINERvA measurements. None of the models or variants were able to successfully reproduce the data across the entire phase space, which includes areas dominated by each interaction channel.