1,117 research outputs found

    Constraining models for the origin of ultra-high-energy cosmic rays with a novel combined analysis of arrival directions, spectrum, and composition data measured at the Pierre Auger Observatory

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    The UHECR dipole and quadrupole in the latest data from the original Auger and TA surface detectors

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    The sources of ultra-high-energy cosmic rays are still unknown, but assuming standard physics, they are expected to lie within a few hundred megaparsecs from us. Indeed, over cosmological distances cosmic rays lose energy to interactions with background photons, at a rate depending on their mass number and energy and properties of photonuclear interactions and photon backgrounds. The universe is not homogeneous at such scales, hence the distribution of the arrival directions of cosmic rays is expected to reflect the inhomogeneities in the distribution of galaxies; the shorter the energy loss lengths, the stronger the expected anisotropies. Galactic and intergalactic magnetic fields can blur and distort the picture, but the magnitudes of the largest-scale anisotropies, namely the dipole and quadrupole moments, are the most robust to their effects. Measuring them with no bias regardless of any higher-order multipoles is not possible except with full-sky coverage. In this work, we achieve this in three energy ranges (approximately 8--16 EeV, 16--32 EeV, and 32--∞ EeV) by combining surface-detector data collected at the Pierre Auger Observatory until 2020 and at the Telescope Array (TA) until 2019, before the completion of the upgrades of the arrays with new scintillator detectors. We find that the full-sky coverage achieved by combining Auger and TA data reduces the uncertainties on the north-south components of the dipole and quadrupole in half compared to Auger-only results

    Transperineal Laser Ablation for Benign Prostatic Enlargement: A Systematic Review and Pooled Analysis of Pilot Studies

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    Transperineal laser ablation (TPLA) of the prostate is a new minimally invasive treatment option in men with lower urinary tract symptoms (LUTS) due to benign prostatic enlargement (BPE). The aim of this systematic review was to investigate the efficacy and safety of TPLA in the management of BPE. The primary outcomes were the improvement in urodynamic parameters (maximum urinary flow (Q(max)) and postvoiding residue (PVR)) and LUTS relief, assessed using the IPSS questionnaire. The secondary outcomes were the preservation of sexual and ejaculatory functions, assessed with the IEEF-5 and MSHQ-EjD questionnaires, respectively, and rates of postoperative complications. We reviewed the literature for prospective or retrospective studies evaluating the use of TPLA in the treatment of BPE. A comprehensive search in PubMed, Scopus, Web of Science, and ClinicalTrials.gov was performed for English language articles published between January 2000 and June 2022. Pooled analysis of the included studies with available follow-up data for the outcomes of interest was additionally performed. After screening 49 records, six full-text manuscripts were identified, including two retrospective and four prospective non-comparative studies. Overall, 297 patients were included. All the studies independently reported a statistically significant improvement, from baseline, in Q(max), PVR, and IPSS score at each timepoint. Three studies additionally demonstrated that TPLA did not affect sexual function, reporting no change in the IEEF-5 score, and a statistically significant improvement in MSHQ-EjD score at each timepoint. Low rates of complications were recorded in all the included studies. Pooled analysis showed a clinically meaningful improvement in both micturition and sexual outcomes mean values at 1, 3, 6, and 12 months of follow-up, compared with baseline. Transperineal laser ablation of the prostate for the treatment of BPE showed interesting results in pilot studies. However, higher level and comparative studies are needed to confirm its efficacy in relieving obstructive symptoms and preserving sexual function

    Radio Measurements of the Depth of Air-Shower Maximum at the Pierre Auger Observatory

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    International audienceThe Auger Engineering Radio Array (AERA), part of the Pierre Auger Observatory, is currently the largest array of radio antenna stations deployed for the detection of cosmic rays, spanning an area of 1717 km2^2 with 153 radio stations. It detects the radio emission of extensive air showers produced by cosmic rays in the 308030-80 MHz band. Here, we report the AERA measurements of the depth of the shower maximum (XmaxX_\text{max}), a probe for mass composition, at cosmic-ray energies between 1017.510^{17.5} to 1018.810^{18.8} eV, which show agreement with earlier measurements with the fluorescence technique at the Pierre Auger Observatory. We show advancements in the method for radio XmaxX_\text{max} reconstruction by comparison to dedicated sets of CORSIKA/CoREAS air-shower simulations, including steps of reconstruction-bias identification and correction, which is of particular importance for irregular or sparse radio arrays. Using the largest set of radio air-shower measurements to date, we show the radio XmaxX_\text{max} resolution as a function of energy, reaching a resolution better than 1515 g cm2^{-2} at the highest energies, demonstrating that radio XmaxX_\text{max} measurements are competitive with the established high-precision fluorescence technique. In addition, we developed a procedure for performing an extensive data-driven study of systematic uncertainties, including the effects of acceptance bias, reconstruction bias, and the investigation of possible residual biases. These results have been cross-checked with air showers measured independently with both the radio and fluorescence techniques, a setup unique to the Pierre Auger Observatory

    UHECR arrival directions in the latest data from the original Auger and TA surface detectors and nearby galaxies

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    The distribution of ultra-high-energy cosmic-ray arrival directions appears to be nearly isotropic except for a dipole moment of order 6×(E/10 EeV)6 \times (E/10~\mathrm{EeV}) per cent. Nonetheless, at the highest energies, as the number of possible candidate sources within the propagation horizon and the magnetic deflections both shrink, smaller-scale anisotropies might be expected to emerge. On the other hand, the flux suppression reduces the statistics available for searching for such anisotropies. In this work, we consider two different lists of candidate sources: a sample of nearby starburst galaxies and the 2MRS catalog tracing stellar mass within 250 Mpc. We combine surface-detector data collected at the Pierre Auger Observatory until 2020 and the Telescope Array until 2019, and use them to test models in which UHECRs comprise an isotropic background and a foreground originating from the candidate sources and randomly deflected by magnetic fields. The free parameters of these models are the energy threshold, the signal fraction, and the search angular scale. We find a correlation between the arrival directions of 11.8%3.1%+5.0%11.8\%_{-3.1\%}^{+5.0\%} of cosmic rays detected with E38 EeVE \ge 38~\mathrm{EeV} by Auger or with E49 EeVE \gtrsim 49~\mathrm{EeV} by TA and the position of nearby starburst galaxies on a 15.53.2+5.3{15.5^\circ}_{-3.2^\circ}^{+5.3^\circ} angular scale, with a 4.2σ post-trial significance, as well as a weaker correlation with the overall galaxy distribution

    Demonstrating Agreement between Radio and Fluorescence Measurements of the Depth of Maximum of Extensive Air Showers at the Pierre Auger Observatory

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    We show, for the first time, radio measurements of the depth of shower maximum (XmaxX_\text{max}) of air showers induced by cosmic rays that are compared to measurements of the established fluorescence method at the same location. Using measurements at the Pierre Auger Observatory we show full compatibility between our radio and the previously published fluorescence data set, and between a subset of air showers observed simultaneously with both radio and fluorescence techniques, a measurement setup unique to the Pierre Auger Observatory. Furthermore, we show radio XmaxX_\text{max} resolution as a function of energy and demonstrate the ability to make competitive high-resolution XmaxX_\text{max} measurements with even a sparse radio array. With this, we show that the radio technique is capable of cosmic-ray mass composition studies, both at Auger and at other experiments.Comment: Submitted to Phys. Rev. Let

    The UHECR dipole and quadrupole in the latest data from the original Auger and TA surface detectors

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    The sources of ultra-high-energy cosmic rays are still unknown, but assuming standard physics, they are expected to lie within a few hundred megaparsecs from us. Indeed, over cosmological distances cosmic rays lose energy to interactions with background photons, at a rate depending on their mass number and energy and properties of photonuclear interactions and photon backgrounds. The universe is not homogeneous at such scales, hence the distribution of the arrival directions of cosmic rays is expected to reflect the inhomogeneities in the distribution of galaxies; the shorter the energy loss lengths, the stronger the expected anisotropies. Galactic and intergalactic magnetic fields can blur and distort the picture, but the magnitudes of the largest-scale anisotropies, namely the dipole and quadrupole moments, are the most robust to their effects. Measuring them with no bias regardless of any higher-order multipoles is not possible except with full-sky coverage. In this work, we achieve this in three energy ranges (approximately 8--16 EeV, 16--32 EeV, and 32--∞ EeV) by combining surface-detector data collected at the Pierre Auger Observatory until 2020 and at the Telescope Array (TA) until 2019, before the completion of the upgrades of the arrays with new scintillator detectors. We find that the full-sky coverage achieved by combining Auger and TA data reduces the uncertainties on the north-south components of the dipole and quadrupole in half compared to Auger-only results

    Cosmological implications of photon-flux upper limits at ultrahigh energies in scenarios of Planckian-interacting massive particles for dark matter

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    Using the data of the Pierre Auger Observatory, we report on a search for signatures that would be suggestive of super-heavy particles decaying in the Galactic halo. From the lack of signal, we present upper limits for different energy thresholds above ≳108 GeV on the secondary by-product fluxes expected from the decay of the particles. Assuming that the energy density of these super-heavy particles matches that of dark matter observed today, we translate the upper bounds on the particle fluxes into tight constraints on the couplings governing the decay process as a function of the particle mass. Instantons, which are nonperturbative solutions to Yang-Mills equations, can give rise to decay channels otherwise forbidden and transform stable particles into metastable ones. Assuming such instanton-induced decay processes, we derive a bound on the reduced coupling constant of gauge interactions in the dark sector: αX ≲ 0.09, for 109 ≲ MX=GeV < 1019. Conversely, we obtain that, for instance, a reduced coupling constant αX ¼ 0.09 excludes masses MX ≳ 3 × 1013 GeV. In the context of dark matter production from gravitational interactions alone during the reheating epoch, we derive constraints on the parameter space that involves, in addition to MX and αX, the Hubble rate at the end of inflation, the reheating efficiency, and the nonminimal coupling of the Higgs with curvature

    Search for photons above 10 19 eV with the surface detector of the Pierre Auger Observatory

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    We use the surface detector of the Pierre Auger Observatory to search for air showers initiated by photons with an energy above 1019^{19} eV. Photons in the zenith angle range from 30∘ to 60∘ can be identified in the overwhelming background of showers initiated by charged cosmic rays through the broader time structure of the signals induced in the water-Cherenkov detectors of the array and the steeper lateral distribution of shower particles reaching ground. Applying the search method to data collected between January 2004 and June 2020, upper limits at 95% CL are set to an E2^{-2} diffuse flux of ultra-high energy photons above 1019^{19} eV, 2 × 1019^{19} eV and 4 × 1019^{19} eV amounting to 2.11 × 103^{-3}, 3.12 × 104^{-4} and 1.72 × 104^{-4} km2^{-2} sr1^{-1} yr1^{-1}, respectively. While the sensitivity of the present search around 2 × 1019^{19} eV approaches expectations of cosmogenic photon fluxes in the case of a pure-proton composition, it is one order of magnitude above those from more realistic mixed-composition models. The inferred limits have also implications for the search of super-heavy dark matter that are discussed and illustrated

    Ground observations of a space laser for the assessment of its in-orbit performance