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  1. We study the static responses of cold quark matter in the intermediate baryonic density region(characterized by a chemical potentialμ) in the presence of a strong-magnetic field. We consider inparticular, the so-called magnetic dual Chiral Density Wave (MDCDW) phase, which is materialized by aninhomogeneous condensate formed by a particle-hole pair. It is shown, that the MDCDW phase is morestable in the weak-coupling regime than the one considered in the magnetic catalysis of chiral symmetrybraking phenomenon and even than the chiral symmetric phase that was expected to be realized atsufficiently high baryonic chemical potential. The different components of the photon polarization operatorofmore »the MDCDW phase in the one-loop approximation are calculated. We found that in the MDCDW phasethere is neither Debye screening nor Meissner effect in the lowest-Landau-level approximation. Theobtained Debye length depends on the amplitudemand modulationbof the inhomogeneous condensateand it is only different from zero if the relation |μ−b|>m holds. But, we found that in the region ofinterest this inequality is not satisfied. Thus, no Debye screening takes place under those conditions. On theother hand, since the particle-hole condensate is electrically neutral, the U(1) electromagnetic group is notbroken by the ground state and consequently there is no Meissner effect. These results can be of interest forthe astrophysics of neutron stars« less
  2. Abstract The production cross-section of a top quark in association with a W boson is measured using proton–proton collisions at $$\sqrt{s} = 8\,\text {TeV}$$ s = 8 TeV . The dataset corresponds to an integrated luminosity of $$20.2\,\text {fb}^{-1}$$ 20.2 fb - 1 , and was collected in 2012 by the ATLAS detector at the Large Hadron Collider at CERN. The analysis is performed in the single-lepton channel. Events are selected by requiring one isolated lepton (electron or muon) and at least three jets. A neural network is trained to separate the tW signal from the dominant $$t{\bar{t}}$$ t tmore »¯ background. The cross-section is extracted from a binned profile maximum-likelihood fit to a two-dimensional discriminant built from the neural-network output and the invariant mass of the hadronically decaying W boson. The measured cross-section is $$\sigma _{tW} = 26 \pm 7\,\text {pb}$$ σ tW = 26 ± 7 pb , in good agreement with the Standard Model expectation.« less
  3. Abstract A measurement of the $$ B_{s}^{0} \rightarrow J/\psi \phi $$ B s 0 → J / ψ ϕ decay parameters using $$ 80.5\, \mathrm {fb^{-1}} $$ 80.5 fb - 1 of integrated luminosity collected with the ATLAS detector from 13  $$\text {Te}\text {V}$$ Te proton–proton collisions at the LHC is presented. The measured parameters include the CP -violating phase $$\phi _{s} $$ ϕ s , the width difference $$ \Delta \Gamma _{s}$$ Δ Γ s between the $$B_{s}^{0}$$ B s 0 meson mass eigenstates and the average decay width $$ \Gamma _{s}$$ Γ s . The values measured formore »the physical parameters are combined with those from $$ 19.2\, \mathrm {fb^{-1}} $$ 19.2 fb - 1 of 7 and 8  $$\text {Te}\text {V}$$ Te data, leading to the following: $$\begin{aligned} \phi _{s}= & {} -0.087 \pm 0.036 ~\mathrm {(stat.)} \pm 0.021 ~\mathrm {(syst.)~rad} \\ \Delta \Gamma _{s}= & {} 0.0657 \pm 0.0043 ~\mathrm {(stat.)}\pm 0.0037 ~\mathrm {(syst.)~ps}^{-1} \\ \Gamma _{s}= & {} 0.6703 \pm 0.0014 ~\mathrm {(stat.)}\pm 0.0018 ~\mathrm {(syst.)~ps}^{-1} \end{aligned}$$ ϕ s = - 0.087 ± 0.036 ( stat . ) ± 0.021 ( syst . ) rad Δ Γ s = 0.0657 ± 0.0043 ( stat . ) ± 0.0037 ( syst . ) ps - 1 Γ s = 0.6703 ± 0.0014 ( stat . ) ± 0.0018 ( syst . ) ps - 1 Results for $$\phi _{s} $$ ϕ s and $$ \Delta \Gamma _{s}$$ Δ Γ s are also presented as 68% confidence level contours in the $$\phi _{s} $$ ϕ s – $$ \Delta \Gamma _{s}$$ Δ Γ s plane. Furthermore the transversity amplitudes and corresponding strong phases are measured. $$\phi _{s} $$ ϕ s and $$ \Delta \Gamma _{s}$$ Δ Γ s measurements are in agreement with the Standard Model predictions.« less
  4. Figure 5b of the paper [1] contained a misinterpretation in the comparison between the reported new ATLAS measurement of the process pp → Xp and previously published CMS data [2]. The ATLAS measurement corresponds to cases where either proton dissociates.
  5. Two additions impacting tables 3 and 4 in ref. [1] are presented in the following. No significant impact is found for other results or figures in ref. [1].
  6. A bstract A search for a chargino-neutralino pair decaying via the 125 GeV Higgs boson into photons is presented. The study is based on the data collected between 2015 and 2018 with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 139 fb − 1 of pp collisions at a centre-of-mass energy of 13 TeV. No significant excess over the expected background is observed. Upper limits at 95% confidence level for a massless $$ {\tilde{\chi}}_1^0 $$ χ ˜ 1 0 are set on several electroweakino production cross-sections and the visible cross-section for beyond the Standard Model processes.more »In the context of simplified supersymmetric models, 95% confidence-level limits of up to 310 GeV in $$ m\left({\tilde{\chi}}_1^{\pm }/{\tilde{\chi}}_2^0\right) $$ m χ ˜ 1 ± / χ ˜ 2 0 , where $$ m\left({\tilde{\chi}}_1^0\right) $$ m χ ˜ 1 0 = 0 . 5 GeV, are set. Limits at 95% confidence level are also set on the $$ {\tilde{\chi}}_1^{\pm }{\tilde{\chi}}_2^0 $$ χ ˜ 1 ± χ ˜ 2 0 cross-section in the mass plane of $$ m\left({\tilde{\chi}}_1^{\pm }/{\tilde{\chi}}_2^0\right) $$ m χ ˜ 1 ± / χ ˜ 2 0 and $$ m\left({\tilde{\chi}}_1^0\right) $$ m χ ˜ 1 0 , and on scenarios with gravitino as the lightest supersymmetric particle. Upper limits at the 95% confidence-level are set on the higgsino production cross-section. Higgsino masses below 380 GeV are excluded for the case of the higgsino fully decaying into a Higgs boson and a gravitino.« less
  7. Abstract The results of a search for electroweakino pair production $$pp \rightarrow \tilde{\chi }^\pm _1 \tilde{\chi }^0_2$$ p p → χ ~ 1 ± χ ~ 2 0 in which the chargino ( $$\tilde{\chi }^\pm _1$$ χ ~ 1 ± ) decays into a W boson and the lightest neutralino ( $$\tilde{\chi }^0_1$$ χ ~ 1 0 ), while the heavier neutralino ( $$\tilde{\chi }^0_2$$ χ ~ 2 0 ) decays into the Standard Model 125 GeV Higgs boson and a second $$\tilde{\chi }^0_1$$ χ ~ 1 0 are presented. The signal selection requires a pair of b -tagged jetsmore »consistent with those from a Higgs boson decay, and either an electron or a muon from the W boson decay, together with missing transverse momentum from the corresponding neutrino and the stable neutralinos. The analysis is based on data corresponding to 139  $$\mathrm {fb}^{-1}$$ fb - 1 of $$\sqrt{s}=13$$ s = 13 TeV pp collisions provided by the Large Hadron Collider and recorded by the ATLAS detector. No statistically significant evidence of an excess of events above the Standard Model expectation is found. Limits are set on the direct production of the electroweakinos in simplified models, assuming pure wino cross-sections. Masses of $$\tilde{\chi }^{\pm }_{1}/\tilde{\chi }^{0}_{2}$$ χ ~ 1 ± / χ ~ 2 0 up to 740 GeV are excluded at 95% confidence level for a massless $$\tilde{\chi }^{0}_{1}$$ χ ~ 1 0 .« less