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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. (2019). Observation of Two Resonances in the Lambda(0)(b)pi(+/-) Systems and Precise Measurement of Sigma(+/-)(b) and Sigma(*+/-)(b) Properties. Phys. Rev. Lett., 122(1), 012001–9pp.
Abstract: The first observation of two structures consistent with resonances in the final states Lambda(0)(b)pi(-) and Lambda(0)(b)pi(+) thorn is reported using samples of pp collision data collected by the LHCb experiment at root s = 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb(-1). The ground states Sigma(+/-)(b) and Sigma(*+/-)(b) are also confirmed and their masses and widths are precisely measured.
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Dombos, A. C., Spyrou, A., Naqvi, F., Quinn, S. J., Liddick, S. N., Algora, A., et al. (2019). beta-decay half-lives of neutron-rich nuclides in the A=100-110 mass region. Phys. Rev. C, 99(1), 015802–8pp.
Abstract: beta-decay half-lives of neutron-rich nuclides in the A = 100-110 mass region have been measured using an implantation station installed inside of the Summing NaI(T1) (SuN) detector at the National Superconducting Cyclotron Laboratory. Accurate half-lives for these nuclides are important for nuclear astrophysics, nuclear structure, and nuclear technology. The half-lives from the present work are compared with previous measurements, showing overall good agreement.
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ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Aparisi Pozo, J. A., Bailey, A. J., Barranco Navarro, L., Cabrera Urban, S., et al. (2019). Search for heavy charged long-lived particles in proton-proton collisions at root s=13 TeV using an ionisation measurement with the ATLAS detector. Phys. Lett. B, 788, 96–116.
Abstract: This Letter presents a search for heavy charged long-lived particles produced in proton-proton collisions at root s= 13 TeV at the LHC using a data sample corresponding to an integrated luminosity of 36.1 fb(-1) collected by the ATLAS experiment in 2015 and 2016. These particles are expected to travel with a velocity significantly below the speed of light, and therefore have a specific ionisation higher than any high-momentum Standard Model particle of unit charge. The pixel subsystem of the ATLAS detector is used in this search to measure the ionisation energy loss of all reconstructed charged particles which traverse the pixel detector. Results are interpreted assuming the pair production of R-hadrons as composite colourless states of a long-lived gluino and Standard Model partons. No significant deviation from Standard Model background expectations is observed, and lifetime-dependent upper limits on R-hadron production cross-sections and gluino masses are set, assuming the gluino always decays to two quarks and a 100 GeV stable neutralino. R-hadrons with lifetimes above 1.0 ns are excluded at the 95% confidence level, with lower limits on the gluino mass ranging between 1290 GeV and 2060 GeV. In the case of stable R-hadrons, the lower limit on the gluino mass at the 95% confidence level is 1890 GeV.
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Barenboim, G., Masud, M., Ternes, C. A., & Tortola, M. (2019). Exploring the intrinsic Lorentz-violating parameters at DUNE. Phys. Lett. B, 788, 308–315.
Abstract: Neutrinos can push our search for new physics to a whole new level. What makes them so hard to be detected, what allows them to travel humongous distances without being stopped or deflected allows to amplify Planck suppressed effects (or effects of comparable size) to a level that we can measure or bound in DUNE. In this work we analyze the sensitivity of DUNE to CPT and Lorentz-violating interactions in a framework that allows a straightforward extrapolation of the bounds obtained to any phenomenological modification of the dispersion relation of neutrinos.
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ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Barranco Navarro, L., Cabrera Urban, S., Castillo Gimenez, V., Cerda Alberich, L., et al. (2019). Search for light resonances decaying to boosted quark pairs and produced in association with a photon or a jet in proton-proton collisions at root s=13 TeV with the ATLAS detector. Phys. Lett. B, 788, 316–335.
Abstract: This Letter presents a search for new light resonances decaying to pairs of quarks and produced in association with a high-p(T) photon or jet. The dataset consists of proton-proton collisions with an integrated luminosity of 36.1 fb(-1) at a centre-of-mass energy of root s = 13 TeV recorded by the ATLAS detector at the Large Hadron Collider. Resonance candidates are identified as massive large-radius jets with substructure consistent with a particle decaying into a quark pair. The mass spectrum of the candidates is examined for local excesses above background. No evidence of a new resonance is observed in the data, which are used to exclude the production of a lepto-phobic axial-vector Z' boson. (C) 2018 The Author(s). Published by Elsevier B.V.
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ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Aparisi Pozo, J. A., Bailey, A. J., Barranco Navarro, L., Cabrera Urban, S., et al. (2019). Search for vector-boson resonances decaying to a top quark and bottom quark in the lepton plus jets final state in pp collisions at root s=13 TeV with the ATLAS detector. Phys. Lett. B, 788, 347–370.
Abstract: A search for new charged massive gauge bosons, W', is performed with the ATLAS detector at the LHC. Data were collected in proton-proton collisions at a center-of-mass energy of root s = 13 TeV and correspond to an integrated luminosity of 36.1 fb(-1). This analysis searches for W' bosons in the W'-> t ( b) over bar decay channel in final states with an electron or muon plus jets. The search covers resonance masses between 0.5 and 5.0 TeV and considers right-handed W' bosons. No significant deviation from the Standard Model (SM) expectation is observed and upper limits are set on theW'-> t ( b) over bar cross section times branching ratio and the W' boson effective couplings as a function of the W' boson mass. For right-handed W' bosons with coupling to the SM particles equal to the SM weak coupling constant, masses below 3.15 TeV are excluded at the 95% confidence level. This search is also combined with a previously published ATLAS result for W'-> t ( b) over bar in the fully hadronic final state. Using the combined searches, right-handed W' bosons with masses below 3.25 TeV are excluded at the 95% confidence level.
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Bandyopadhyay, P., Chun, E. J., Mandal, R., & Queiroz, F. S. (2019). Scrutinizing right-handed neutrino portal dark matter with Yukawa effect. Phys. Lett. B, 788, 530–534.
Abstract: Analyzing the neutrino Yukawa effect in the freeze-out process of a generic dark matter candidate with right-handed neutrino portal, we identify the parameter regions satisfying the observed dark matter relic density as well as the current Fermi-LAT and H.E.S.S. limits and the future CTA reach on gamma-ray signals. In this scenario the dark matter couples to the Higgs boson at one-loop level and thus could be detected by spin-independent nucleonic scattering for a reasonable range of the relevant parameters.
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NA48/2 Collaboration(Batley, J. R. et al), & Fiorini, L. (2019). First observation and study of the K-+/- -> pi(+/-)pi(0)e(+)e(-) decay. Phys. Lett. B, 788, 552–561.
Abstract: The NA48/2 experiment at CERN reports the first observation of the K-+/- -> pi(+/-)pi(0)e(+)e(-) decay from an exposure of 1.7 x 10(11) charged kaon decays recorded in 2003-2004. A sample of 4919 candidates with 4.9% background contamination allows the determination of the branching ratio in the full kinematic region, BR(K-+/- -> pi(+/-)pi(0)e(+)e(-)) = (4.24 +/- 0.14) x 10(-6). The study of the kinematic space shows evidence for a structure dependent contribution in agreement with predictions based on chiral perturbation theory. Several P- and CP-violating asymmetries are also evaluated.
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ANTARES, I. C., LIGO and Virgo Collaborations(Albert, A. et al), Barrios-Marti, J., Coleiro, A., Colomer, M., Hernandez-Rey, J. J., Illuminati, G., et al. (2019). Search for Multimessenger Sources of Gravitational Waves and High-energy Neutrinos with Advanced LIGO during Its First Observing Run, ANTARES, and IceCube. Astrophys. J., 870(2), 134–16pp.
Abstract: Astrophysical sources of gravitational waves, such as binary neutron star and black hole mergers or core-collapse supernovae, can drive relativistic outflows, giving rise to non-thermal high-energy emission. High-energy neutrinos are signatures of such outflows. The detection of gravitational waves and high-energy neutrinos from common sources could help establish the connection between the dynamics of the progenitor and the properties of the outflow. We searched for associated emission of gravitational waves and high-energy neutrinos from astrophysical transients with minimal assumptions using data from Advanced LIGO from its first observing run O1, and data from the ANTARES and IceCube neutrino observatories from the same time period. We focused on candidate events whose astrophysical origins could not be determined from a single messenger. We found no significant coincident candidate, which we used to constrain the rate density of astrophysical sources dependent on their gravitational-wave and neutrino emission processes.
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Lopez-Honorez, L., Mena, O., & Villanueva-Domingo, P. (2019). Dark matter microphysics and 21 cm observations. Phys. Rev. D, 99(2), 023522–12pp.
Abstract: Dark matter interactions with massless or very light standard model particles, as photons or neutrinos, may lead to a suppression of the matter power spectrum at small scales and of the number of low mass haloes. Bounds on the dark matter scattering cross section with light degrees of freedom in such interacting dark matter (IDM) scenarios have been obtained from e.g., early time cosmic microwave background physics and large scale structure observations. Here we scrutinize dark matter microphysics in light of the claimed 21 cm EDGES 78 MHz absorption signal. IDM is expected to delay the 21 cm absorption features due to collisional damping effects. We identify the astrophysical conditions under which the existing constraints on the dark matter scattering cross section could be largely improved due to the IDM imprint on the 21 cm signal, providing also an explicit comparison to the WDM scenario.
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