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Rinaldi, M., & Vento, V. (2022). Glueballs at high temperature within the hard-wall holographic model. Eur. Phys. J. C, 82(2), 140–10pp.
Abstract: In this investigation an holographic description of the deconfined phase transition of scalar and tensor glueballs is presented within the so called hard-wall model. The spectra of these bound states of gluons have been calculated from the linearized Einstein equations for a graviton propagating from a thermal AdS(5) space to an AdS Black-Hole. In this framework, the deconfined phase is reached via a two steps mechanism. We propose that the transition between the AdS thermal sector to the BH is described via a first order phase transition, with discontinuous masses at the critical temperature, which has been determined by Herzog's method of regulating the free energy densities. Then, the glueball masses diverge with increasing T in the BH phase and thus lead to deconfined states a la Hagedorn.
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Biryukov, V. M., & Ruiz Vidal, J. (2022). Improved experimental layout for dipole moment measurements at the LHC. Eur. Phys. J. C, 82(2), 149–11pp.
Abstract: The electric and magnetic dipole moment of charm and bottom baryons can be measured for the first time by using bent crystal technology at the LHC. The experimental method, proposed in recent years, suffers from limited statistics, which dominates the uncertainty of the measurement. In this work, we present an alternative experimental layout, based on the use of crystal lenses, that improves the trapping efficiency by about a factor 15 (35) for a 2-cm (5-mm) target with respect to the nominal layout, with plain crystal faces. The efficiencies are evaluated taking into account the constraints from the LHC machine, and the technical challenges to realize this novel experimental method are discussed.
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Baeza-Ballesteros, J., Donini, A., & Nadal-Gisbert, S. (2022). Dynamical measurements of deviations from Newton's 1/r(2) law. Eur. Phys. J. C, 82(2), 154–30pp.
Abstract: In Ref. Donini and Marimon (Eur Phys J C 76:696, arXiv:1609.05654, 2016), an experimental setup aiming at the measurement of deviations from the Newtonian 1/r(2) distance dependence of gravitational interactions was proposed. The theoretical idea behind this setup was to study the trajectories of a “Satellite” with a mass m(S) similar to O(10(-9)) g around a “Planet” with mass m(P) is an element of [10(-7), 10(-5)] g, looking for precession of the orbit. The observation of such feature induced by gravitational interactions would be an unambiguous indication of a gravitational potential with terms different from 1/r and, thus, a powerful tool to detect deviations from Newton's 1/r(2) law. In this paper we optimize the proposed setup in order to achieve maximal sensitivity to look for such Beyond-Newtonian corrections. We then study in detail possible background sources that could induce precession and quantify their impact on the achievable sensitivity. We finally conclude that a dynamical measurement of deviations from newtonianity can test Yukawa-like corrections to the 1/r potential with strength as low as alpha similar to 10(-2) for distances as small as lambda similar to 10 μm.
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Hagedorn, C., Kriewald, J., Orloff, J., & Teixeira, A. M. (2022). Flavour and CP symmetries in the inverse seesaw. Eur. Phys. J. C, 82(3), 194–32pp.
Abstract: We consider an inverse seesaw mechanism of neutrino mass generation in which the Standard Model is extended by 3 + 3 (heavy) sterile states, and endowed with a flavour symmetry G(f), G(f) = Delta(3n(2)) or G(f) = Delta(6n(2)), and a CP symmetry. These symmetries are broken in a peculiar way, so that in the charged lepton sector a residual symmetry G(l) is preserved, while the neutral fermion sector remains invariant under the residual symmetry G(nu) = Z(2) x CP. We study the concrete setup, where the Majorana mass term for three of the sterile states conserves G(nu), while the remaining mass terms (i.e. couplings of left-handed leptons and heavy sterile states, as well as the Dirac-type couplings among the latter) do not break the flavour or CP symmetry. We perform a comprehensive analysis of lepton mixing for different classes of residual symmetries, giving examples for each of these, and study in detail the impact of the additional sterile states on the predictions for lepton mixing. We further confront our results with those obtained in the model-independent scenario, in which the light neutrino mass matrix leaves the residual symmetry G(nu) intact. We consider the phenomenological impact of the inverse seesaw mechanism endowed with flavour and CP symmetries, in particular concerning effects of non-unitarity of the lepton mixing matrix (which strongly constrain the parameter space of the scenario), prospects for neutrinoless double beta decay and for charged lepton flavour violating processes.
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Dai, L. R., Oset, E., & Geng, L. S. (2022). The D-s(+)->pi(+KSKS0)-K-0 reaction and the I=1 partner of the f(0)(1710) state. Eur. Phys. J. C, 82(3), 225–9pp.
Abstract: We have identified the decay modes of the D-s(+)-> pi K+*K+*(-),pi+K*(0)(K) over bar*(0) reactions producing a pion and two vector mesons. The posterior vector-vector interaction generates two resonances that we associate to the f(0)(1710) and the a(0)(1710) recently claimed, and they decay to the observed K+K- or (KSKS0)-K-0 pair, leading to the reactions D-s(+)->pi+K+K-,pi(+KSKS0)-K-0. The results depend on two parameters related to external and internal emission. We determine a narrow region of the parameters consistent with the large N-c limit within uncertainties which gives rise to decay widths in agreement with experiment. With this scenario we make predictions for the branching ratio of the a(0)(1710) contribution to the D-s(+)->pi(K+KS0)-K-0 reaction, finding values within the range of (1.3 +/- 0.4)x10(-3). Comparison of these predictions with coming experimental results on that latter reaction will be most useful to deepen our understanding on the nature of these two resonances.
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ATLAS Collaboration(Aad, G. et al), Aparisi Pozo, J. A., Bailey, A. J., Cabrera Urban, S., Cardillo, F., Castillo Gimenez, V., et al. (2022). Measurement of the energy response of the ATLAS calorimeter to charged pions from W-+/- -> tau(+/-) (->pi(+/-)nu(tau))nu(tau) events in Run 2 data. Eur. Phys. J. C, 82(3), 223–31pp.
Abstract: The energy response of the ATLAS calorimeter is measured for single charged pions with transverse momentum in the range 10<p(T) < 300 GeV. The measurement is performed using 139 fb(-1) of LHC proton-proton collision data at root s =13 TeV taken in Run 2 by the ATLAS detector. Charged pions originating from tau-lepton decays are used to provide a sample of high-p(T) isolated particles, where the composition is known, to test an energy regime that has not previously been probed by in situ single-particle measurements. The calorimeter response to single-pions is observed to be overestimated by similar to 2% across a large part of the p(T) spectrum in the central region and underestimated by similar to 4% in the endcaps in the ATLAS simulation. The uncertainties in the measurements are less than or similar to 1% for 15<p(T) <185 GeV in the central region. To investigate the source of the discrepancies, the width of the distribution of the ratio of calorimeter energy to track momentum, the energies per layer and response in the hadronic calorimeter are also compared between data and simulation.
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Ikeno, N., Bayar, M., & Oset, E. (2021). Combined theoretical study of the D+ -> pi(+) eta eta and D+ -> pi(+)pi(0) eta reactions. Eur. Phys. J. C, 81(4), 377–10pp.
Abstract: We study the D+ -> pi(+) eta eta and D+ -> pi(+)pi(0) eta reactions, which are single Cabibbo suppressed and can proceed both through internal and external emission. The primary mechanisms at quark level are considered, followed by hadronization to produce three mesons in the D+ decay, and after that the final state interaction of these mesons leads to the production of the a(0)(980) resonance, seen in the pi(+)eta, pi(0)eta mass distributions. The theory has three unknown parameters to determine the shape of the distributions and the ratio between the D+ -> pi(+) eta eta and D+ -> pi(+)pi(0) eta rates. This ratio restricts much the sets of parameters but there is still much freedom leading to different shapes in the mass distributions. We call for a measurement of these mass distributions that will settle the reaction mechanism, while at the same time provide relevant information on the way that the a(0)(980) resonance is produced in the reactions.
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ATLAS Collaboration(Aad, G. et al), Aparisi Pozo, J. A., Bailey, A. J., Cabrera Urban, S., Cardillo, F., Castillo Gimenez, V., et al. (2022). The ATLAS inner detector trigger performance in pp collisions at 13 TeV during LHC Run 2. Eur. Phys. J. C, 82(3), 206–57pp.
Abstract: The design and performance of the inner detector trigger for the high level trigger of the ATLAS experiment at the Large Hadron Collider during the 2016-2018 data taking period is discussed. In 2016, 2017, and 2018 the ATLAS detector recorded 35.6 fb(-1), 46.9 fb(-1), and 60.6 fb(-1) respectively of proton-proton collision data at a centre-of-mass energy of 13TeV. In order to deal with the very high interaction multiplicities per bunch crossing expected with the 13TeV collisions the inner detector trigger was redesigned during the long shutdown of the Large Hadron Collider from 2013 until 2015. An overview of these developments is provided and the performance of the tracking in the trigger for the muon, electron, tau and b-jet signatures is discussed. The high performance of the inner detector trigger with these extreme interaction multiplicities demonstrates how the inner detector tracking continues to lie at the heart of the trigger performance and is essential in enabling the ATLAS physics programme.
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Belle II Collaboration(Abudinen, F. et al), & Marinas, C. (2022). B-flavor tagging at Belle II. Eur. Phys. J. C, 82(4), 283–29pp.
Abstract: We report on new flavor tagging algorithms developed to determine the quark-flavor content of bottom (B) mesons at Belle II. The algorithms provide essential inputs for measurements of quark-flavor mixing and charge-parity violation. We validate and evaluate the performance of the algorithms using hadronic B decays with flavor-specific final states reconstructed in a data set corresponding to an integrated luminosity of 62.8 fb(-1), collected at the gamma(4S) resonance with the Belle II detector at the SuperKEKB collider. We measure the total effective tagging efficiency to be epsilon(eff) = (30.0 +/- 1.2(stat) +/- 0.4(syst))% for a category-based algorithm and epsilon(eff) = (28.8 +/- 1.2(stat) +/- 0.4(syst))% for a deep-learning-based algorithm.
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KM3NeT Collaboration(Aiello, S. et al), Alves Garre, S., Calvo, D., Carretero, V., Colomer, M., Garcia Soto, A., et al. (2022). Implementation and first results of the KM3NeT real-time core-collapse supernova neutrino search. Eur. Phys. J. C, 82(4), 317–16pp.
Abstract: The KM3NeT research infrastructure is unconstruction in the Mediterranean Sea. KM3NeT will study atmospheric and astrophysical neutrinos with two multi-purpose neutrino detectors, ARCA and ORCA, primarily aimed at GeV-PeV neutrinos. Thanks to the multi-photomultiplier tube design of the digital optical modules, KM3NeT is capable of detecting the neutrino burst from a Galactic or near-Galactic core-collapse supernova. This potential is already exploitable with the first detection units deployed in the sea. This paper describes the real-time implementation of the supernova neutrino search, operating on the two KM3NeT detectors since the first months of 2019. A quasi-online astronomy analysis is introduced to study the time profile of the detected neutrinos for especially significant events. The mechanism of generation and distribution of alerts, as well as the integration into the SNEWS and SNEWS 2.0 global alert systems, are described. The approach for the follow-up of external alerts with a search for a neutrino excess in the archival data is defined. Finally, an overview of the current detector capabilities and a report after the first two years of operation are given.
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