63 research outputs found

    Nuclear and partonic dynamics in the EMC effect

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    It has been recently confirmed that the magnitude of the EMC effect measured in electron deep inelastic scattering is linearly related to the Short Range Correlation scaling factor obtained from electron inclusive scattering. By using a xx-rescaling approach we are able to understand the interplay between the quark-gluon and hadronic degrees of freedom in the discussion of the EMC effect.Comment: 5 pages, 6 figures, 2 table. We have incorporated SLAC data and redone the calculation with the newest ROOT 5.3

    Multipole decomposition of the cross section of the neutrino-lead scattering process 208Pb(g.s.)(ν,ν)208Pb∗

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    We calculate neutral-current contributions to the process ν+208Pb(g.s)→ ν′+208Pb∗, for incoming neutrino energies up to 150 MeV. The spectrum of 208Pb is calculated by performing a diagonalization of the δ-force interaction in the space of particle-hole pairs, both for neutrons and protons. We study the dependence of the cross section on the energy of the neutrino and present its multipole decomposition for normal and abnormal parity states. We compare our results to the estimate of neutral-current contributions by other authors, and to our previous results for the charged-current channel.Instituto de Física La Plat

    LHC updated hadronic interaction packages analyzed up to cosmic-ray energies

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    The results of high energy simulated experiments where a given hadronic particle impacts on a given target are statistically analyzed. The energy range of the projectiles goes from below the LHC scale up to the highest cosmic ray energies. This study was carried out by using the pre- and post-LHC versions of the hadronic interaction models QGSJET, EPOS and SIBYLL. Our analysis indicates that the post-LHC models present smaller differences in various quantities that characterize the secondary particles produced after the hadronic collisions, in comparison with the corresponding differences that are found comparing the respective old (pre-LHC) versions of the hadronic models. However, it is also found that there exist some discrepancies among models that persist even at the LHC energy scale, that call for further theoretical investigation. An additional analysis of the impact that different modeling of hadronic collisions has on air shower development is also included. It consists of a detailed study of the impact of the different pre- and post-LHC versions of the hadronic models considered, for relevant observables like the muon production depth distribution.Fil: Calcagni, Laura Randa. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: García Canal, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; ArgentinaFil: Sciutto, Sergio Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; ArgentinaFil: Tarutina, Tatiana. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin

    Scaler mode of the Auger Observatory and sunspots

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    Recent data from the Auger Observatory on low-energy secondary cosmic ray particles are analyzed to study temporal correlations together with data on the daily sunspot numbers and neutron monitor data. Standard spectral analysis demonstrates that the available data show 1/f β fluctuations with β ≈ 1 in the low-frequency range. All data behave like Brownian fluctuations in the high-frequency range. The existence of long-range correlations in the data was confirmed by detrended fluctuation analysis. The real data confirmed the correlation between the scaling exponent of the detrended analysis and the exponent of the spectral analysis.Instituto de Física La Plat

    Disentangling the Seesaw in the Left-Right Model -- An Algorithm for the General Case

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    Senjanovic and Tello have analyzed how one could determine the neutrino Dirac mass matrix in the minimal left-right model, assuming that the mass matrices for the light and heavy neutrinos could be taken as inputs. They have provided an analytical solution for the Dirac mass matrix in the case that the left-right symmetry is implemented via a generalized parity symmetry and that this symmetry remains unbroken in the Dirac Yukawa sector. We extend the work of Senjanovic and Tello to the case in which the generalized parity symmetry is broken in the Dirac Yukawa sector. In this case the elegant method outlined by Senjanovic and Tello breaks down and we need to adopt a numerical approach. Several iterative approaches are described; these are found to work in some cases but to be highly unstable in others. A stable, prescriptive numerical algorithm is described that works in all but a vanishingly small number of cases. We apply this algorithm to numerical data sets that are consistent with current experimental constraints on neutrino masses and mixings. We also provide some additional context and supporting explanations for the case in which the parity symmetry is unbroken.Comment: 34 pages, 4 figures; published versio

    Deuteron structure in the deep inelastic regime

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    We study nuclear effects in the deuteron in the deep inelastic regime using the newest available data. We put special emphasis on their Q2 dependence. The study is carried out using a scheme which parameterizes, in a simple manner, these effects by changing the proton and neutron stucture functions in medium. The result of our analysis is compared with other recent proposals. We conclude that precise EMC ratios cannot be obtained without considering the nuclear effects in the deuteronInstituto de Física La Plat

    Nuclear and partonic dynamics in the EMC effect

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    It has been recently confirmed that the magnitude of the EMC effect measured in the electron deep inelastic scattering is linearly related to the short-range correlation scaling factor obtained from electron inclusive scattering. By using a x-rescaling approach we are able to understand the interplay between the quark-gluon and hadronic degrees of freedom in the discussion of the EMC effect.Instituto de Física La Plat

    Quasiparticle-rotor model description of carbon isotopes

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    In this work we perform quasiparticle-rotor coupling model calculations within the usual BCS and the projected BCS for the carbon isotopes 15C, 17C and 19C using 13C as the building block. Owing to the pairing correlation, we find that 13C as well as the cores of the other isotopes, namely 14C, 16C and 18C acquire strong and varied deformations. The deformation parameter is large and negative for 12C, very small (or zero) for 14C and large and positive for 16C and 18C. This finding casts a doubt about the purity of the supposed simple one-neutron halo nature of 19C.Instituto de Física La PlataFacultad de Ciencias Astronómicas y Geofísica

    Nuclear response to dark matter signals in Ge and Xe odd-mass targets

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    The interaction of dark matter particles (WIMPs) with the odd-mass 73 Ge and131 Xe target nuclei is analyzed, in the context of the minimal extensions of the SUSYmodel. The BCS+QRPA technique plus the quasiparticle-phonon coupling scheme isused to describe the nuclear structure part of the calculations. The resulting values forthe nuclear spin content of both nuclei are compared with values previously reported inthe literature.Fil: Sáez, María Manuela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of California at Berkeley; Estados Unidos. Universidad Nacional de La Plata; ArgentinaFil: Civitarese, Enrique Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Tarutina, Tatiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Fushimi, Keiko Juliana. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Área Física Teórica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Exploring unsupervised top tagging using Bayesian inference

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    Recognizing hadronically decaying top-quark jets in a sample of jets, or even its total fraction in the sample, is an important step in many LHC searches for Standard Model and Beyond Standard Model physics as well. Although there exists outstanding top-tagger algorithms, their construction and their expected performance rely on Montecarlo simulations, which may induce potential biases. For these reasons we develop two simple unsupervised top-tagger algorithms based on performing Bayesian inference on a mixture model. In one of them we use as the observed variable a new geometrically-based observable A~3\tilde{A}_{3}, and in the other we consider the more traditional τ3/τ2\tau_{3}/\tau_{2} NN-subjettiness ratio, which yields a better performance. As expected, we find that the unsupervised tagger performance is below existing supervised taggers, reaching expected Area Under Curve AUC 0.800.81\sim 0.80-0.81 and accuracies of about 69% - 75% in a full range of sample purity. However, these performances are more robust to possible biases in the Montecarlo that their supervised counterparts. Our findings are a step towards exploring and considering simpler and unbiased taggers.Comment: 15 pages, 6 figure
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