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ATLAS Collaboration(Aad, G. et al), Alvarez Piqueras, D., Aparisi Pozo, J. A., Bailey, A. J., Cabrera Urban, S., Castillo, F. L., et al. (2020). Measurement of the Lund Jet Plane Using Charged Particles in 13 TeV Proton-Proton Collisions with the ATLAS Detector. Phys. Rev. Lett., 124(22), 222002–21pp.
Abstract: The prevalence of hadronic jets at the LHC requires that a deep understanding of jet formation and structure is achieved in order to reach the highest levels of experimental and theoretical precision. There have been many measurements of jet substructure at the LHC and previous colliders, but the targeted observables mix physical effects from various origins. Based on a recent proposal to factorize physical effects, this Letter presents a double-differential cross-section measurement of the Lund jet plane using 139 fb(-1) of root s = 13 TeV proton-proton collision data collected with the ATLAS detector using jets with transverse momentum above 675 GeV. The measurement uses charged particles to achieve a fine angular resolution and is corrected for acceptance and detector effects. Several parton shower Monte Carlo models are compared with the data. No single model is found to be in agreement with the measured data across the entire plane.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., et al. (2020). Observation of New Xi(0)(c) Baryons Decaying to Lambda K-+(c)-. Phys. Rev. Lett., 124(22), 222001–11pp.
Abstract: The Lambda K-+(c)- mass spectrum is studied with a data sample of pp collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 5.6 fb(-1) collected by the LHCb experiment. Three Xi(0)(c) states are observed with a large significance and their masses and natural widths are measured to be m[Xi(c)(2923)(0)] = 2923.04 +/- 0.25 +/- 0.20 +/- 0.14 MeV, Gamma[Xi(c)(2923)(0)] = 7.1 +/- 0.8 +/- 1.8 MeV, m[Xi(c)(2939)(0)] = 2938.55 +/- 0.21 +/- 0.17 +/- 0.14 MeV, Gamma[Xi(c)(2939)(0)] = 10.2 +/- 0.8 +/- 1.1 MeV, m[Xi(c)(2965)(0)] = 2964.88 +/- 0.26 +/- 0.14 +/- 0.14 MeV, Gamma[Xi(c)(2965)(0)] = 14.1 +/- 0.9 +/- 1.3 MeV, where the uncertainties are statistical, systematic, and due to the limited knowledge of the Lambda(+)(c) mass. The Xi(c)(2923)(0) and Xi(c)(2939)(0) baryons are new states. The Xi(c)(2965)(0) state is in the vicinity of the known Xi(c)(2970)(0) baryon; however, their masses and natural widths differ significantly.
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AGATA Collaboration(Korten, W. et al), & Gadea, A. (2020). Physics opportunities with the Advanced Gamma Tracking Array: AGATA. Eur. Phys. J. A, 56(5), 137–33pp.
Abstract: New physics opportunities are opening up by the Advanced Gamma Tracking Array, AGATA, as it evolves to the full 4 pi instrument. AGATA is a high-resolution gamma -ray spectrometer, solely built from highly segmented high-purity Ge detectors, capable of measuring gamma rays from a few tens of keV to beyond 10 MeV, with unprecedented efficiency, excellent position resolution for individual gamma -ray interactions, and very high count-rate capability. As a travelling detector AGATA will be employed at all major current and near-future European research facilities delivering stable and radioactive ion beams.
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ANTARES Collaboration(Albert, A. et al), Colomer, M., Gozzini, R., Hernandez-Rey, J. J., Illuminati, G., Khan-Chowdhury, N. R., et al. (2020). Search for neutrino counterparts of gravitational-wave events detected by LIGO and Virgo during run O2 with the ANTARES telescope. Eur. Phys. J. C, 80(5), 487–9pp.
Abstract: An offline search for a neutrino counterpart to gravitational -wave (GW) events detected during the second observation run (02) of Advanced-LIGO and Advanced Virgo performed with ANTARES data is presented. In addition to the search for long tracks induced by pp, (17i,) charged current interactions, a search for showering events induced by interactions of neutrinos of any flavour is conducted. The severe spatial and time coincidence provided by the gravitational -wave alert allows regions above the detector horizon to be probed, extending the ANTARES sensitivity over the entire sky. The results of this all -neutrino -flavour and all -sky time dependent analysis are presented. The search for prompt neutrino emission within 500 s around the time of six GW events yields no neutrino counterparts. Upper limits on the neutrino spectral fluence and constraints on the isotropic energy radiated via high-energy neutrinos (from a few TeV to a few tens of PeV) are set for each GW event analysed.
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Gisbert, H., & Ruiz Vidal, J. (2020). Improved bounds on heavy quark electric dipole moments. Phys. Rev. D, 101(11), 115010–5pp.
Abstract: New bounds on the electric dipole moment (EDM) of charm and bottom quarks are derived using the stringent limits on their chromo-EDMs. The new limits, vertical bar d(c)vertical bar < 1.5 x 10(-21) e cm and vertical bar d(b)vertical bar < 1.2 x 10(-20) e cm, improve the previous ones by about 3 orders of magnitude. These indirect bounds have implications for different models of new physics, including two-Higgs-doublet, leptoquarks, and supersymmetry models.
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