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Abstract:

Measurements of the total and differential Higgs boson production cross-sections, via WH and ZH associated production using H → WW* → ℓνℓν and H → WW* → ℓνjj decays, are presented. The analysis uses proton-proton events delivered by the Large Hadron Collider at a centre-of-mass energy of 13 TeV and recorded by the ATLAS detector between 2015 and 2018. The data correspond to an integrated luminosity of 140 fb−1. The sum of the WH and ZH cross-sections times the H → WW* branching fraction is measured to be 0.44−0.09+0.10stat.−0.05+0.06syst. pb, in agreement with the Standard Model prediction. Higgs boson production is further characterised through measurements of the differential cross-section as a function of the transverse momentum of the vector boson and in the framework of Simplified Template Cross-Sections.

Abstract:

<jats:p>Understanding electron neutrino interactions is crucial for measurements of neutrino oscillations and searches for new physics in neutrino experiments. We present the first measurement of the flux-averaged <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msub><a:mrow><a:mi>ν</a:mi></a:mrow><a:mrow><a:mi>e</a:mi></a:mrow></a:msub><a:mo>+</a:mo><a:msub><a:mrow><a:mover accent="true"><a:mrow><a:mi>ν</a:mi></a:mrow><a:mrow><a:mo stretchy="false">¯</a:mo></a:mrow></a:mover></a:mrow><a:mrow><a:mi>e</a:mi></a:mrow></a:msub></a:mrow></a:math> charged-current single charged-pion production cross section on argon using the MicroBooNE detector and data from the NuMI neutrino beam. The total cross section is measured to be <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mrow><e:mo stretchy="false">[</e:mo><e:mn>0.93</e:mn><e:mo>±</e:mo><e:mn>0.13</e:mn><e:mo stretchy="false">(</e:mo><e:mi>stat</e:mi><e:mo stretchy="false">)</e:mo><e:mo>±</e:mo><e:mn>0.27</e:mn><e:mo stretchy="false">(</e:mo><e:mi>syst</e:mi><e:mo stretchy="false">)</e:mo><e:mo stretchy="false">]</e:mo><e:mo>×</e:mo><e:msup><e:mrow><e:mn>10</e:mn></e:mrow><e:mrow><e:mo>−</e:mo><e:mn>39</e:mn></e:mrow></e:msup><e:mtext> </e:mtext><e:mtext> </e:mtext><e:msup><e:mrow><e:mi>cm</e:mi></e:mrow><e:mrow><e:mn>2</e:mn></e:mrow></e:msup><e:mo>/</e:mo><e:mi>nucleon</e:mi></e:mrow></e:math> at a mean <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"><m:mrow><m:msub><m:mrow><m:mi>ν</m:mi></m:mrow><m:mrow><m:mi>e</m:mi></m:mrow></m:msub><m:mo>+</m:mo><m:msub><m:mrow><m:mover accent="true"><m:mrow><m:mi>ν</m:mi></m:mrow><m:mrow><m:mo stretchy="false">¯</m:mo></m:mrow></m:mover></m:mrow><m:mrow><m:mi>e</m:mi></m:mrow></m:msub></m:mrow></m:math> energy of 730��MeV. Differential cross sections are also reported in electron energy, electron and pion angles, and electron-pion opening angle.</jats:p>

Abstract:

A measurement is presented of elliptic ( $v_2$ ) and triangular ( $v_3$ ) azimuthal anisotropy coefficients for charged particles produced in $\mathrm{Pb}+\mathrm{Pb}$ collisions at $\sqrt{s_{{}_{\text{NN}}}}=5.02��\text{TeV}$ using a dataset corresponding to an integrated luminosity of $0.44{\text{nb}}^{-1}$ collected with the ATLAS detector at the LHC in 2018. The values of $v_2$ and $v_3$ are measured for charged particles over a wide range of transverse momentum ( $p_{\text{T}}$ ), 1–400 $\text{GeV}$ , and $\mathrm{Pb}+\mathrm{Pb}$ collision centrality, 0–60%, using the scalar-product and multiparticle cumulant methods. These methods are sensitive to event-by-event fluctuations and nonflow effects in the measurements of azimuthal anisotropies. Positive values of $v_2$ are observed up to a $p_{\text{T}}$ of approximately 100 $\text{GeV}$ from both methods across all centrality intervals. Positive values of $v_3$ are observed up to approximately 25 $\text{GeV}$ using both methods, though the application of the three-subevent technique to the multiparticle cumulant method leads to significant changes at the highest $p_{\text{T}}$ . At high $p_{\text{T}}$ ( $p_{\text{T}}⪆10��\text{GeV}$ ), charged particles are dominantly from jet fragmentation. These jets, and hence the measurements presented here, are sensitive to the path-length dependence of parton energy loss in the quark-gluon plasma produced in $\mathrm{Pb}+\mathrm{Pb}$ collisions.

Abstract:

We report the first measurement of neutron capture multiplicity in neutrino-oxygen neutral-current quasielasticlike interactions at the gadolinium-loaded Super-Kamiokande detector using the T2K neutrino beam, which has a peak energy of about 0.6��GeV. A total of 30 neutral-current quasielasticlike event candidates were selected from T2K data corresponding to an exposure of $1.76\times {10}^{20}$ protons on target. The $\gamma$ ray signals resulting from neutron captures were identified using a neural network. The flux-averaged mean neutron capture multiplicity was measured to be ${1.37\pm 0.33(\mathrm{stat}.)}_{-0.27}^{+0.17}(\mathrm{syst}.)$ , which is compatible within 2.3 sigma than predictions obtained using our nominal simulation. We discuss potential sources of systematic uncertainty in the prediction and demonstrate that a significant portion of this discrepancy arises from the modeling of hadron-nucleus interactions in the detector medium.