6062 research outputs found
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<math altimg="si1.svg"><msubsup><mrow><mi mathvariant="normal">K</mi></mrow><mrow><mi mathvariant="normal">S</mi></mrow><mrow><mn>0</mn></mrow></msubsup></math> and <math altimg="si2.svg"><mi mathvariant="normal">Λ</mi><mo stretchy="false">(</mo><mover accent="true"><mrow><mi mathvariant="normal">Λ</mi></mrow><mo>‾</mo></mover><mo stretchy="false">)</mo></math> two-particle femtoscopic correlations in PbPb collisions at <math altimg="si3.svg"><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><mi mathvariant="normal">NN</mi></mrow></msub></mrow></msqrt><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>5.02</mn><mspace width="0.2em"/><mtext>TeV</mtext></math>
No full textTwo-particle correlations are presented for KS0, Image 1, and Image 2 strange hadrons as a function of relative momentum in lead-lead collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The dataset corresponds to an integrated luminosity of 0.607nb−1 and was collected using the CMS detector at the CERN LHC. These correlations are sensitive to quantum statistics and to final-state interactions between the particles. The source size extracted from the KS0KS0 correlations is found to decrease from 4.6 to 1.6fm in going from central to peripheral collisions. Strong interaction scattering parameters (i.e., scattering length and effective range) are determined from the Image 3 and Image 4 (including their charge conjugates) correlations using the Lednický–Lyuboshitz model and are compared to theoretical and other experimental results
Search for pair production of squarks or gluinos decaying via sleptons or weak bosons in final states with two same-sign or three leptons with the ATLAS detector
No full textA search for pair production of squarks or gluinos decaying via sleptons or weak bosons is reported. The search targets a final state with exactly two leptons with same-sign electric charge or at least three leptons without any charge requirement. The analysed data set corresponds to an integrated luminosity of 139 fb of proton-proton collisions collected at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Multiple signal regions are defined, targeting several SUSY simplified models yielding the desired final states. A single control region is used to constrain the normalisation of the WZ + jets background. No significant excess of events over the Standard Model expectation is observed. The results are interpreted in the context of several supersymmetric models featuring R-parity conservation or R-parity violation, yielding exclusion limits surpassing those from previous searches. In models considering gluino (squark) pair production, gluino (squark) masses up to 2.2 (1.7) TeV are excluded at 95% confidence level.[graphic not available: see fulltext
Amplitude Analysis of the <math display="inline"><mrow><msup><mrow><mi>B</mi></mrow><mrow><mn>0</mn></mrow></msup><mo stretchy="false">→</mo><msup><mrow><mi>K</mi></mrow><mrow><mo>*</mo><mn>0</mn></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>-</mo></mrow></msup></mrow></math> Decay
No full textAn amplitude analysis of the B0→K*0μ+μ- decay is presented using a dataset corresponding to an integrated luminosity of 4.7 fb-1 of pp collision data collected with the LHCb experiment. For the first time, the coefficients associated to short-distance physics effects, sensitive to processes beyond the standard model, are extracted directly from the data through a q2-unbinned amplitude analysis, where q2 is the μ+μ- invariant mass squared. Long-distance contributions, which originate from nonfactorizable QCD processes, are systematically investigated, and the most accurate assessment to date of their impact on the physical observables is obtained. The pattern of measured corrections to the short-distance couplings is found to be consistent with previous analyses of b- to s-quark transitions, with the largest discrepancy from the standard model predictions found to be at the level of 1.8 standard deviations. The global significance of the observed differences in the decay is 1.4 standard deviations
Multiplicity and event-scale dependent flow and jet fragmentation in pp collisions at = 13 TeV and in p–Pb collisions at = 5.02 TeV
No full textLong- and short-range correlations for pairs of charged particles are studied via two-particle angular correlations in pp collisions at = 13 TeV and p–Pb collisions at = 5.02 TeV. The correlation functions are measured as a function of relative azimuthal angle ∆φ and pseudorapidity separation ∆η for pairs of primary charged particles within the pseudorapidity interval |η| < 0.9 and the transverse-momentum interval 1 < p< 4 GeV/c. Flow coefficients are extracted for the long-range correlations (1.6 < |∆η| < 1.8) in various high-multiplicity event classes using the low-multiplicity template fit method. The method is used to subtract the enhanced yield of away-side jet fragments in high-multiplicity events. These results show decreasing flow signals toward lower multiplicity events. Furthermore, the flow coefficients for events with hard probes, such as jets or leading particles, do not exhibit any significant changes compared to those obtained from high-multiplicity events without any specific event selection criteria. The results are compared with hydrodynamic-model calculations, and it is found that a better understanding of the initial conditions is necessary to describe the results, particularly for low-multiplicity events
Search for the decay of the Higgs boson to a boson and a light pseudoscalar particle decaying to two photons
No full textA search for the decay of the Higgs boson to a boson and a light, pseudoscalar particle, , decaying respectively to two leptons and to two photons is reported. The search uses the full LHC Run 2 proton-proton collision data at TeV, corresponding to 139 fb collected by the ATLAS detector. This is one of the first searches for this specific decay mode of the Higgs boson, and it probes unexplored parameter space in models with axion-like particles (ALPs) and extended scalar sectors. The mass of the particle is assumed to be in the range 0.1-33 GeV. The data are analysed in two categories: a merged category where the photons from the decay are reconstructed in the ATLAS calorimeter as a single cluster, and a resolved category in which two separate photons are detected. The main background processes are from Standard Model boson production in association with photons or jets. The data are in agreement with the background predictions, and upper limits on the branching ratio of the Higgs boson decay to times the branching ratio are derived at the 95% confidence level and they range from 0.08% to 2% depending on the mass of the particle. The results are also interpreted in the context of ALP models
Have pulsar timing array methods detected a cosmological phase transition?
No full textWe show that the recent detection of a gravitational wave (GW) background reported by various pulsar timing array (PTA) collaborations including NANOGrav-15 yr, PPTA, EPTA/InPTA, and CPTA can be explained in terms of first order phase transitions (FOPTs) from dark sector models (DSM). Specifically, we explore a model for first order phase transitions that involves the Majoron, a Nambu-Goldstone boson that is emerging from the spontaneous symmetry breaking of a U(1)L or U(1)B-L symmetry. We show how the predicted GW power spectrum, with a realistic choice of the FOPT parameters, is consistent with 1-σ deviations from the estimated parameters of the background detected by the PTA collaborations
Form factors of the tricritical three-state Potts model in its scaling limit
No full textWe compute the form factors of the order and disorder operators, together with those of the stress–energy tensor, of a two-dimensional three-state Potts model with vacancies along its thermal deformation at the critical point. At criticality, the model is described by the non-diagonal partition function of the unitary minimal model of conformal field theories and is accompanied by an internal S symmetry. The off-critical thermal deformation is an integrable massive theory that is still invariant under S. The presence of infinitely many conserved quantities, whose spin spectrum is related to the exceptional Lie algebra E, allows us to determine the analytic S-matrix, the exact mass spectrum and the matrix elements of local operators of this model in an exact non-perturbative way. We use the spectral representation series of the correlators and the fast convergence of these series to compute several universal ratios of the renormalization group
Beam spin asymmetry measurements of deeply virtual π0 production with CLAS12
No full textThe new experimental measurements of beam spin asymmetry were performed for the deeply virtual exclusive π0 production in a wide kinematic region with the photon virtualities Q2 up to 6.6 GeV<sup>2</sup> and the Bjorken scaling variable xB in the valence regime. The data were collected by the CEBAF Large Acceptance Spectrometer (CLAS12) at Jefferson Lab with longitudinally polarized 10.6 GeV electrons scattered on an unpolarized liquid-hydrogen target. Sizable asymmetry values indicate a substantial contribution from transverse virtual photon amplitudes to the polarized structure functions. The interpretation of these measurements in terms of the Generalized Parton Distributions (GPDs) demonstrates their sensitivity to the chiral-odd GPD E¯T, which contains information on quark transverse spin densities in unpolarized and polarized nucleons and provides access to the nucleon's transverse anomalous magnetic moment. Additionally, the data were compared to a theoretical model based on a Regge formalism that was extended to the high photon virtualities
Banca dati geologica F. 609 Termini Imerese scala 1:25.000
Get PDF<p>Banca Dati alla scala 1:25.000 della Carta Geologica prodotta nell'ambito del Progetto CARG in formato GeoPackage. I layer presenti si riferiscono alle Unità cartografabili geologiche, agli Elementi geomorfologici e alle Risorse e Prospezioni. Gli strati informativi sono rappresentati in accordo con la simbologia prevista dalla normativa del Progetto CARG.</p>
Development of a new CEDAR for kaon identification at the NA62 experiment at CERN
No full textThe NA62 experiment at CERN utilises a differentialCherenkov counter with achromatic ring focus (CEDAR) for taggingkaons within an unseparated monochromatic beam of chargedhadrons. The CEDAR-H detector was developed to minimise the amountof material in the path of the beam by using hydrogen gas as theradiator medium. The detector was shown to satisfy the kaon taggingrequirements in a test-beam before installation and commissioning atthe experiment. The CEDAR-H performance was measured using NA62data collected in 2023