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Measurement of branching fractions for <math display="inline"><mrow><msubsup><mrow><mi mathvariant="normal">Λ</mi></mrow><mrow><mi>c</mi></mrow><mrow><mo>+</mo></mrow></msubsup><mo stretchy="false">→</mo><mi>n</mi><msubsup><mrow><mi>K</mi></mrow><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup></mrow></math> and <math display="inline"><mrow><msubsup><mrow><mi mathvariant="normal">Λ</mi></mrow><mrow><mi>c</mi></mrow><mrow><mo>+</mo></mrow></msubsup><mo stretchy="false">→</mo><mi>n</mi><msubsup><mrow><mi>K</mi></mrow><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup></mrow></math>
No full textBased on 4.5 fb-1 of e+e- collision data accumulated at center-of-mass energies between 4599.53 and 4698.82 MeV with the BESIII detector, we measure the absolute branching fraction of the Cabibbo-favored decay Λc+→nKS0π+ with the precision improved by a factor of 2.8 and report the first evidence for the singly-Cabibbo-suppressed decay Λc+→nKS0K+. The branching fractions for Λc+→nKS0π+ and Λc+→nKS0K+ are determined to be (1.86±0.08±0.04)×10-2 and (3.9-1.4+1.7±0.3)×10-4, respectively, where the first uncertainties are statistical and the second ones are systematic
First Observation of a Three-Resonance Structure in <math display="inline"><mrow><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>-</mo></mrow></msup><mo stretchy="false">→</mo><mtext>Nonopen</mtext></mrow></math> Charm Hadrons
No full textWe report the measurement of the inclusive cross sections for e+e-→nOCH (where nOCH denotes non-open charm hadrons) with improved precision at center-of-mass (c.m.) energies from 3.645 to 3.871 GeV. We observe three resonances: R(3760), R(3780), and R(3810) with significances of 8.1σ, 13.7σ, and 8.8σ, respectively. The R(3810) state is observed for the first time, while the R(3760) and R(3780) states are observed for the first time in the nOCH cross sections. Two sets of resonance parameters describe the energy-dependent line shape of the cross sections well. In set I [set II], the R(3810) state has mass (3805.7±1.1±2.7) [(3805.7±1.1±2.7)] MeV/c2, total width (11.6±2.9±1.9) [(11.5±2.8±1.9)] MeV, and an electronic width multiplied by the nOCH decay branching fraction of (10.9±3.8±2.5) [(11.0±3.4±2.5)] eV. In addition, we measure the branching fractions B[R(3760)→nOCH]=(25.2±16.1±30.4)%[(6.4±4.8±7.7)%] and B[R(3780)→nOCH]=(12.3±6.6±8.3)%[(10.4±4.8±7.0)%] for the first time. The R(3760) state can be interpreted as an open-charm (OC) molecular state, but containing a simple four-quark state component. The R(3810) state can be interpreted as a hadrocharmonium state
Observation of and decays
No full textThe decays and are observed for the first time, in proton-proton collision data at , corresponding to an integrated luminosity of 5.4 collected with the LHCb detector. Their ratios of branching fractions with respect to the mode are measured to be where the first uncertainties are statistical, the second systematic, and the third, for the decays, are due to the uncertainties on the branching fractions of the and decay modes. The measured branching fractions probe factorization assumptions in effective theories and provide the normalization for future pentaquark searches in decay channels
Constraints on metastable superheavy dark matter coupled to sterile neutrinos with the Pierre Auger Observatory
No full textDark matter particles could be superheavy, provided their lifetime is much longer than the age of the Universe. Using the sensitivity of the Pierre Auger Observatory to ultrahigh energy neutrinos and photons, we constrain a specific extension of the Standard Model of particle physics that meets the lifetime requirement for a superheavy particle by coupling it to a sector of ultralight sterile neutrinos. Our results show that, for a typical dark coupling constant of 0.1, the mixing angle θm between active and sterile neutrinos must satisfy, roughly, θm≲1.5×10-6(MX/109 GeV)-2 for a mass MX of the dark-matter particle between 108 GeV and 1011 GeV
Study of excited <math display="inline"><mrow><mi mathvariant="normal">Ξ</mi></mrow></math> states in <math display="inline"><mrow><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><msup><mrow><mi>K</mi></mrow><mrow><mo>-</mo></mrow></msup><mi mathvariant="normal">Λ</mi><msup><mrow><mover accent="true"><mrow><mi mathvariant="normal">Ξ</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow><mrow><mo>+</mo></mrow></msup><mo>+</mo><mi mathvariant="normal">c</mi><mo>.</mo><mi mathvariant="normal">c</mi><mo>.</mo></mrow></math>
No full textBased on a sample of (448.1±2.9)×106 ψ(3686) events collected with the BESIII detector at BEPCII, the decays of ψ(3686)→K-ΛΞ¯++c.c. with Ξ¯+→Λ¯π+, Λ¯→p¯π+ are studied. We investigate the two excited resonances, Ξ(1690)- and Ξ(1820)-, which are each observed with large significance (≫10σ) in the K-Λ invariant mass distributions. A partial wave analysis is performed, and the spin-parities of Ξ(1690)- and Ξ(1820)- are measured to be 12- and 32-, respectively. The masses, widths, and product branching fractions of Ξ(1690)- and Ξ(1820)- are also measured
Euclid preparation - XXXIX. The effect of baryons on the halo mass function
No full textThe Euclid photometric survey of galaxy clusters stands as a powerful cosmological tool, with the capacity to significantly propel our understanding of the Universe. Despite being subdominant to dark matter and dark energy, the baryonic component of our Universe holds substantial influence over the structure and mass of galaxy clusters. This paper presents a novel model that can be used to precisely quantify the impact of baryons on the virial halo masses of galaxy clusters using the baryon fraction within a cluster as a proxy for their effect. Constructed on the premise of quasi-adiabaticity, the model includes two parameters, which are calibrated using non-radiative cosmological hydrodynamical simulations, and a single large-scale simulation from the Magneticum set, which includes the physical processes driving galaxy formation. As a main result of our analysis, we demonstrate that this model delivers a remarkable 1% relative accuracy in determining the virial dark matter-only equivalent mass of galaxy clusters starting from the corresponding total cluster mass and baryon fraction measured in hydrodynamical simulations. Furthermore, we demonstrate that this result is robust against changes in cosmological parameters and against variation of the numerical implementation of the subresolution physical processes included in the simulations. Our work substantiates previous claims regarding the impact of baryons on cluster cosmology studies. In particular, we show how neglecting these effects would lead to biased cosmological constraints for a Euclid-like cluster abundance analysis. Importantly, we demonstrate that uncertainties associated with our model arising from baryonic corrections to cluster masses are subdominant when compared to the precision with which mass–observable (i.e. richness) relations will be calibrated using Euclid and to our current understanding of the baryon fraction within galaxy clusters.Key words: galaxies: clusters: general / cosmology: theory / large-scale structure of Univers
Determination of short- and long-distance contributions in <math display="inline"><msup><mi>B</mi><mn>0</mn></msup><mo stretchy="false">→</mo><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>-</mo></msup></math> decays
No full textAn amplitude analysis of the B0→K*0μ+μ- decay is presented. The analysis is based on data collected by the LHCb experiment from proton-proton collisions at s=7, 8 and 13 TeV, corresponding to an integrated luminosity of 4.7 fb-1. For the first time, Wilson coefficients and nonlocal hadronic contributions are accessed directly from the unbinned data, where the latter are parametrized as a function of q2 with a polynomial expansion. Wilson coefficients and nonlocal hadronic parameters are determined under two alternative hypotheses: the first relies on experimental information alone, while the second one includes information from theoretical predictions for the nonlocal contributions. Both models obtain similar results for the parameters of interest. The overall level of compatibility with the Standard Model is evaluated to be between 1.8 and 1.9 standard deviations when looking at the C9 Wilson coefficient alone, and between 1.3 and 1.4 standard deviations when considering the full set of C9,C10,C9′ and C10′ Wilson coefficients. The ranges reflect the theoretical assumptions made in the analysis
Momentum scale calibration of the LHCb spectrometer
No full textFor accurate determination of particle masses accurateknowledge of the momentum scale of the detectors is crucial. Theprocedure used to calibrate the momentum scale of the LHCbspectrometer is described and illustrated using the performanceobtained with an integrated luminosity of 1.6 fbcollected during 2016 in pp running. The procedure uses largesamples of J/ψ → μμ andB → J/ψK decays and leads to a relative accuracyof 3 × 10 on the momentum scale
Scienza aperta e diritti dell'autore per l'accesso equo alla conoscenza
Get PDF<p>Presentato al convegno del progetto Right2Pub Roma, giugno 2024</p>
Note Illustrative della Carta geologica d'Italia alla scala 1:50.000 F. 180 Salsomaggiore Terme, Servizio Geologico d'Italia - ISPRA
No full text<p>Note illustrative redatte per il Foglio geologico n. 180 Salsomaggiore Terme della Carta Geologica d'Italia alla scala 1:50.000. 112 pp.</p>