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Measurement of b-quark fragmentation properties in jets using the decay B ± → J/ψK ± in pp collisions at √s = 13 TeV with the ATLAS detector
(Springer Science and Business Media Deutschland GmbH, 2021-12) Aad, G.; Abbott, B.; Abbott, D.C.; Abed Abud, A.; Abeling, K.; Abhayasinghe, D.K.; Abidi, S.H.; AbouZeid, O.S.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Abusleme Hoffman, A.C.; Acharya, B.S.; Achkar, B.; Adam, L.; Adam Bourdarios, C.; Adamczyk, L.; Adamek, L.; Adelman, J.; Adiguzel, A.; Adorni, S.; Adye, T.; Affolder, A.A.; Afik, Y.; Agapopoulou, C.; Agaras, M.N.; Agarwala, J.; Aggarwal, A.; Agheorghiesei, C.; Aguilar-Saavedra, J.A.; Ahmad, A.; Ahmadov, F.; Ahmed, W.S.; Ai, X.; Aielli, G.; Akatsuka, S.; Akbiyik, M.; Åkesson, T.P.A.; Akimov, A.V.; Al Khoury, K.; Alberghi, G.L.; Albert, J.; Alconada Verzini, M.J.; Alderweireldt, S.; Aleksa, M.; Aleksandrov, I.N.; Alexa, C.; Alexopoulos, T.; Alfonsi, A.; Alfonsi, F.; Alhroob, M.; Ali, B.; Ali, S.; Aliev, M.; Alimonti, G.; Allaire, C.; Allbrooke, B.M.M.; Allport, P.P.; Aloisio, A.; Alonso, F.
The fragmentation properties of jets containing b-hadrons are studied using charged B mesons in 139 fb−1 of pp collisions at s = 13 TeV, recorded with the ATLAS detector at the LHC during the period from 2015 to 2018. The B mesons are reconstructed using the decay of B± into J/ψK±, with the J/ψ decaying into a pair of muons. Jets are reconstructed using the anti-kt algorithm with radius parameter R = 0.4. The measurement determines the longitudinal and transverse momentum profiles of the reconstructed B hadrons with respect to the axes of the jets to which they are geometrically associated. These distributions are measured in intervals of the jet transverse momentum, ranging from 50 GeV to above 100 GeV. The results are corrected for detector effects and compared with several Monte Carlo predictions using different parton shower and hadronisation models. The results for the longitudinal and transverse profiles provide useful inputs to improve the description of heavy-flavour fragmentation in jets. [Figure not available: see fulltext.]. © 2021, The Author(s).
Search for charginos and neutralinos in final states with two boosted hadronically decaying bosons and missing transverse momentum in pp collisions at s =13 TeV with the ATLAS detector
(American Physical Society, 2021-12-01) Aad, G.; Abbott, B.; Abbott, D.C.; Abed Abud, A.; Abeling, K.; Abhayasinghe, D.K.; Abidi, S.H.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Abusleme Hoffman, A.C.; Acharya, B.S.; Achkar, B.; Adam, L.; Adam Bourdarios, C.; Adamczyk, L.; Adamek, L.; Addepalli, S.V.; Adelman, J.; Adiguzel, A.; Adorni, S.; Adye, T.; Affolder, A.A.; Afik, Y.; Agapopoulou, C.; Agaras, M.N.; Agarwala, J.; Aggarwal, A.; Agheorghiesei, C.; Aguilar-Saavedra, J.A.; Ahmad, A.; Ahmadov, F.; Ahmed, W.S.; Ai, X.; Aielli, G.; Aizenberg, I.; Akatsuka, S.; Akbiyik, M.; Åkesson, T.P.A.; Akimov, A.V.; Al Khoury, K.; Alberghi, G.L.; Albert, J.; Albicocco, P.; Alconada Verzini, M.J.; Alderweireldt, S.; Aleksa, M.; Aleksandrov, I.N.; Alexa, C.; Alexopoulos, T.; Alfonsi, A.; Alfonsi, F.; Alhroob, M.; Ali, B.; Ali, S.; Aliev, M.; Alimonti, G.; Allaire, C.; Allbrooke, B.M.M.; Allport, P.P.
A search for charginos and neutralinos at the Large Hadron Collider using fully hadronic final states and missing transverse momentum is reported. Pair-produced charginos or neutralinos are explored, each decaying into a high-pT Standard Model weak boson. Fully hadronic final states are studied to exploit the advantage of the large branching ratio, and the efficient rejection of backgrounds by identifying the high-pT bosons using large-radius jets and jet substructure information. An integrated luminosity of 139 fb-1 of proton-proton collision data collected by the ATLAS detector at a center-of-mass energy of 13 TeV is used. No significant excess is found beyond the Standard Model expectation. Exclusion limits at the 95% confidence level are set on wino or higgsino production with various assumptions about the decay branching ratios and the type of lightest supersymmetric particle. A wino (higgsino) mass up to 1060 (900) GeV is excluded when the lightest supersymmetry particle mass is below 400 (240) GeV and the mass splitting is larger than 400 (450) GeV. The sensitivity to high-mass winos and higgsinos is significantly extended relative to previous LHC searches using other final states. © 2021 CERN, for the ATLAS Collaboration. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.
Toward a search for axionlike particles at the LNLS
(American Physical Society, 2023-09) Angel L.; Arias P.; Dib C.O.; De Jesus A.S.; Kuleshov S.; Kozhuharov V.; Lin L.; Lindner M.; Queiroz F.S.; Silva R.C.; Villamizar Y.
Axionlike particles (ALPs) appear in several dark sector studies. They have gained increasing attention from the theoretical and experimental community. In this work, we propose the first search for ALPs to be conducted at the Brazilian Synchrotron Light Laboratory (LNLS). In this work, we derive the projected sensitivity of a proposed experiment for the production of ALPs via the channel e+e-→aγ. We show that such an experiment could probe ALP masses between 1-55 MeV, and ALP-electron couplings down to gaee=2-6×10-4 GeV-1 depending on the energy beam, thickness of the target, and background assumptions. Therefore, this quest would cover an unexplored region of parameter space for experiments of this kind, constitute a promising probe for dark sectors, and potentially become the first Latin-American dark sector detector. © 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.
Analysis of Local and Global Aromaticity in Si3C5 and Si4C8 Clusters. Aromatic Species Containing Planar Tetracoordinate Carbon
(MDPI, 2021-12) Torres-Vega, Juan J.; Alcoba, Diego R.; Oña, Ofelia B.; Vásquez-Espinal, Alejandro; Báez-Grez, Rodrigo; Lain, Luis; Torre, Alicia; García, Víctor; Tiznado, William
The minimum energy structures of the Si3C5 and Si4C8 clusters are planar and contain planar tetracoordinate carbons (ptCs). These species have been classified, qualitatively, as global (π) and local (σ) aromatics according to the adaptive natural density partitioning (AdNDP) method, which is an orbital localization method. This work evaluates these species’ aromaticity, focusing on confirming and quantifying their global and local aromatic character. For this purpose, we use an orbital localization method based on the partitioning of the molecular space according to the topology of the electronic localization function (LOC-ELF). In addition, the magnetically induced current density is analyzed. The LOC-ELF-based analysis coincides with the AdNDP study (double aromaticity, global, and local). Moreover, the current density analysis detects global and local ring currents. The strength of the global and local current circuit is significant, involving 4n + 2 π-and σ-electrons, respectively. The latter implicates the Si-ptC-Si fragment, which would be related to the 3c-2e σ-bond detected by the orbital localization methods in this fragment. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Matrix Effect of Properties of Au, ZnO and Eu2O3: Silica, Titania and Alumina Matrices
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-09) Díaz, Carlos; Cifuentes-Vaca, Olga; Valenzuela, María Luisa
The composites Au/SiO2, Au/TiO2, Au/Al2O3, ZnO/TiO2, ZnO/TiO2, ZnO/Al2O3 and Eu2O3/SiO2, Eu2O3/TiO2 and Eu2O3/Al2O3 were prepared using a solid-state method. The effect of the polymer precursors was investigated using two precursor polymers, Chitosan and Poly(styrene-co-4vinylpyridine), (PS-co-4-PVP) in the M/MxLy•Chitosan//M’xO’y as well as M/MxLy•PS-co-4-PVP//M’xO’y with M’xO’y = SiO2, TiO2 and Al2O3. The effects on the particle size and morphology were observed. The new composites were characterized using X-ray powder diffraction, SEM-EDS mapping and HRTEM analysis. The distribution of the metallic nanoparticles as well as the metal oxide nanoparticles inside the matrices depend on the matrix. Marked optical and photocatalytic effects of the Au, ZnO and Eu2O3 inside the SiO2, TiO2 and Al2O3 matrices are expected. An experiment is in course. © 2023 by the authors.
Asymptotic black holes and conformal mass in AdS quadratic curvature gravity
(American Physical Society, 2023-09) Miskovic, Olivera; Olea, Rodrigo; Papantonopoulos, Eleftherios; Parra-Cisterna, Yoel
We explore the consistent truncation of conserved charges in quadratic curvature gravity (QCG) with anti-de Sitter asymptotics to the linear order in the Weyl tensor. The QCG action is given by the most general curvature-squared corrections to Einstein gravity, and it is suitably rendered finite by the addition of extrinsic counterterms (Kounterterms). The conserved charges derived from this action are, as a consequence, nonlinear in the spacetime Riemann tensor. A detailed analysis of the falloff of generic static solutions leads to a charge proportional to the electric part of the Weyl tensor, without loss of information on the energy of the system. The procedure followed provides firmer ground to the extension of the notion of Conformal Mass to higher-curvature gravity, as it appears as associated to a renormalized action. We observe that criticality condition in QCG poses an obstruction to the charge linearization, in contrast to previous results in Lovelock gravity, where degeneracy condition plays a key role. © 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.
Why is phenyl azide so unreactive in [3 + 2] cycloaddition reactions? Demystifying Sustmann's paradigmatic parabola
(Royal Society of Chemistry, 2023-09) Domingo, Luis R.; Ríos-Gutiérrez, Mar; Pérez, Patricia
The [3 + 2] cycloaddition (32CA) reactions of phenyl azide with a series of 25 ethylenes of different electronic activation have been studied within Molecular Electron Density Theory (MEDT) at the ωB97X-D/6-311G(d,p) computational level to understand the low reactivity of azides participating in 32CA reactions. Analysis of the reactivity indices allows characterizing phenyl azide as a moderate electrophile and a moderate nucleophile. The relative reaction rate constants kr of twelve selected 32CA reactions, together with the electrophilicity ω and nucleophilicity N indices of the corresponding ethylenes, allow us to classify these 32CA reactions into four groups: (i) group A, involving supernucleophilic ethylenes and displaying a kr > 104; (ii) group B, involving strained cyclic ethylenes and displaying a kr < 102; (iii) group C, involving strongly electrophilic ethylenes and displaying a kr ≤ 102, and (iv) group D, involving moderately electrophilic and nucleophilic ethylenes and displaying a kr < 2. These four groups are characterized in Sustmann's “parabolic correlation”, which results from an inaccurate interpretation of the reactivity of phenyl azide, which is not an “ambiphilic species” but rather a moderate electrophile that reacts efficiently only with supernucleophilic ethylenes in reverse electron density flux (REDF) zw-type 32CA reactions. © 2023 The Royal Society of Chemistry.
Documentary Analysis of Hypericum perforatum (St. John’s Wort) and Its Effect on Depressive Disorders
(Multidisciplinary Digital Publishing Institute (MDPI), 0024-12) Otero, María Carolina; Ceric, Francisco; Miranda-Rojas, Sebastián; Carreño, Carolina; Atala, Cristian; Ramírez-Barrantes, Ricardo; Gordillo-Fuenzalida, Felipe
Hypericum perforatum, also known as St. John’s Wort, pericon, or yellow grass, is known for its antidepressant potential. It could represent a natural alternative to current pharmacological antidepressant treatments, which have a high incidence of side effects in patients and therefore lead to early dropouts. Through a bibliographic revision of clinical trials and information collected from scientific articles during the first period of 2020, we aimed to evaluate whether its administration could be beneficial in the treatment of mild-to-moderate depression, with fewer side effects compared to synthetic drugs. Among the main components, hypericin and hyperforin have been related to the observed antidepressant activity; therefore, their possible mechanism of action was reviewed and highlighted. Furthermore, patients receiving Hypericum extracts were less likely to withdraw from studies because of adverse effects compared to those receiving older standard antidepressants. This review aims to provide suggestions for an alternative treatment of mild-to-moderate depression disorder under the supervision of a medical doctor, since, although it appears to be a potentially efficient treatment with a low presence of adverse effects in comparison to synthetic antidepressants, it might also interact with other medications and lead to therapeutic failures if misused for self-medication. © 2024 by the authors.
PS J2107-1611: A new wide-separation, quadruply imaged lensed quasar with flux ratio anomalies
(EDP Sciences, 2023-11) Dux, Frédéric; Lemon, Cameron; Courbin, Frédéric; Sluse, Dominique; Smette, Alain; Anguita, Timo; Neira, Favio
We report the discovery of PS J2107-1611, a fold-configuration 4.3′′-separation quadruply lensed quasar with a bright lensed arc. It was discovered using a convolutional neural network on Pan-STARRS gri images of pre-selected quasar candidates with multiple nearby Pan-STARRS detections. Spectroscopic follow-up with EFOSC2 on the ESO 3.58 m New Technology Telescope reveals the source to be a quasar at z = 2.673, with the blended fold image pair showing deformed broad lines relative to the other images. The flux ratios measured from optical to near-infrared imaging in the Canada-France-Hawaii Telescope Legacy Survey, Pan-STARRS, the Legacy Surveys, and the Vista Hemisphere Survey are inconsistent with a smooth mass model as the fold pair images are ∼15 times too faint. Variability, time delay effects, and reddening are ruled out through multiple-epoch imaging and color information. The system is marginally resolved in the radio in the Very Large Array Sky Survey S-band, where it has a 10 mJy detection. The radio flux ratios are compatible with the smooth mass macromodel. This system offers a unique tool for future studies of quasar structure with strong and microlensing. A more detailed analysis of follow-up with JWST/MIRI, VLT/MUSE, VLT/ERIS, and data from the European Very Long Baseline Interferometer will be presented in a forthcoming paper. © 2023 EDP Sciences. All rights reserved.
The evolution of low-mass central galaxies in the vicinity of massive structures and its impact on the two-halo conformity
(EDP Sciences, 0025-12) Palma, Daniela; Lacerna, Ivan; Celeste Artale M.; Montero-Dorta, Antonio D.; Ruiz, Andrés N; Cora, Sofía A; Rodriguez, Facundo; Pallero, Diego; O'mill, Ana; Choque-Challapa, Nelvy
We investigated the population of low-mass central galaxies with M∗ = 109.5-1010 h-1 M⊙, inhabiting regions near massive groups and clusters of galaxies using the IllustrisTNG300 and MDPL2-SAG simulations. We set out to study their evolutionary histories, aiming to find hints about the large-scale conformity signal they produce. We also used a control sample of central galaxies with the same stellar mass range located far away from massive structures. For both samples, we find a subpopulation of galaxies accreted by another halo in the past, but now considered central galaxies; we refer to these objects as former satellites. The number of former satellites is higher for quenched central galaxies near massive systems, with fractions of 45% and 17% in Illustris TNG300 and MDPL2-SAG, respectively. The differences in the numerical resolution of each simulation lead to the different fractions of former satellites. Our results in TNG300 show that former satellites "pollute"the sample of central galaxies because they suffered environmental processes when they were satellites hosted typically by massive dark matter halos (M200 ≥ 1013 h-1 M⊙) since z ≲ 0.5. After removing former satellites, the evolutionary trends for quenched central galaxies near massive structures are fairly similar to those of the quenched control galaxies, showing small differences at low redshift. For MDPL2-SAG instead, former satellites were hosted by less massive halos, with a mean halo mass around 1011.4 h-1 M⊙, and the evolutionary trends remain equal before and after removing former satellite galaxies. We also measured the two-halo conformity, that is, the correlation in the specific star formation rate between lowmass central galaxies and their neighbors at megaparsec scales, and how former satellites contribute to the signal at three different redshifts: z = 0, 0.3, and 1. The time evolution of the conformity signal in the simulations presents apparent contradictory results: it decreases from z = 0 to z = 1 in MDPL2-SAG, while it increases in TNG300. However, after removing former satellites in the latter, the signal is strongly reduced, but practically does not change at z = 0.3, and it disappears at z = 1. We compare our findings with recent literature data and discuss the conformity measurements, as different approaches can lead to varying results. © The Authors 2025.
A hidden active galactic nucleus powering bright [O III] nebulae in a protocluster at z = 4.5 revealed by JWST
(EDP Sciences, 0025-12) Solimano M.; González-López J.; Aravena M; Alcalde Pampliega B.; Assef R.J.; Béthermin M.; Boquien M.; Bovino S.; Casey C.M. j; Cassata P.; Da Cunha E; Davies R.L.
Galaxy protoclusters are sites of rapid growth, with a high density of massive galaxies driving elevated rates of star formation and accretion onto supermassive black holes. Here, we present new JWST/NIRSpec IFU observations of the J1000+0234 group at z = 4.54, a dense region of a protocluster hosting a massive, dusty star forming galaxy (DSFG). The new data reveal two extended, high-equivalent-width (EW0 > 1000 Å) [O III] nebulae that appear at both sides of the DSFG along its minor axis (namely O3-N and O3-S). On one hand, the spectrum of O3-N shows a broad and blueshifted component with a full width at half maximum (FWHM) of ∼1300 km s-1, suggesting an outflow origin. On the other hand, O3-S stretches over 8.6 kpc, and has a velocity gradient that spans 800 km s-1, but shows no evidence of a broad component. However, both sources seem to be powered at least partially by an active galactic nucleus (AGN), so we classified them as extended emission-line regions (EELRs). The strongest evidence comes from the detection of the high-ionization [Ne V] λ 3427 line toward O3-N, which paired with the lack of hard X-rays implies an obscuring column density above the Compton-thick regime. The [Ne V] line is not detected in O3-S, but we measure a He II λ 687 /Hβ = 0.25, which is well above the expectation for star formation. Despite the remarkable alignment of O3-N and O3-S with two radio sources, we do not find evidence of shocks from a radio jet that could be powering the EELRs. We interpret this as O3-S being externally irradiated by the AGN, akin to the famous Hanny's Voorwerp object in the local Universe. In addition, more classical line ratio diagnostics (e.g., [O III]/Hβ vs [N II]/Hα) put the DSFG itself in the AGN region of the diagrams, and therefore suggest it to be the most probable AGN host. These results showcase the ability of JWST to unveil obscured AGN at high redshifts. © The Authors 2025.
Observation of quantum entanglement with top quarks at the ATLAS detector
(Nature Research, 0024-09) Zwalinski L.; Zou W; Zormpa O; Zorbas T.G; Zoch K; Zoccoli A; Živković L.; Ziolkowski M.; Zinsser J.; Zimine N.I.; Zhukov K.; Zhuang X
Entanglement is a key feature of quantum mechanics1–3, with applications in fields such as metrology, cryptography, quantum information and quantum computation4–8. It has been observed in a wide variety of systems and length scales, ranging from the microscopic9–13 to the macroscopic14–16. However, entanglement remains largely unexplored at the highest accessible energy scales. Here we report the highest-energy observation of entanglement, in top–antitop quark events produced at the Large Hadron Collider, using a proton–proton collision dataset with a centre-of-mass energy of √s = 13 TeV and an integrated luminosity of 140 inverse femtobarns (fb)−1 recorded with the ATLAS experiment. Spin entanglement is detected from the measurement of a single observable D, inferred from the angle between the charged leptons in their parent top- and antitop-quark rest frames. The observable is measured in a narrow interval around the top–antitop quark production threshold, at which the entanglement detection is expected to be significant. It is reported in a fiducial phase space defined with stable particles to minimize the uncertainties that stem from the limitations of the Monte Carlo event generators and the parton shower model in modelling top-quark pair production. The entanglement marker is measured to be D = −0.537 ± 0.002 (stat.) ± 0.019 (syst.) for 340GeV
Decoding the formation of hammerhead ion populations observed by Parker Solar Probe
(EDP Sciences, 0024-12) Shaaban, Shaaban M; Lazar M; López R.A.; Yoon P.H.; Poedts S
Context. In situ observations by the Parker Solar Probe (PSP) have revealed new properties of the proton velocity distributions (VDs), including hammerhead features that suggest a non-isotropic broadening of the beams. Aims. The present work proposes a very plausible explanation for the formation of hammerhead proton populations through the action of a proton firehose-like instability triggered by the proton beam. Methods. We investigated a self-generated firehose-like instability driven by the relative drift of ion populations using a simplified moment-based quasi-linear (QL) theory. While simpler and faster than advanced numerical simulations, this toy model provided rapid insights and concisely highlighted the role of plasma micro-instabilities in relaxing the observed anisotropies of particle VDs in the solar wind and space plasmas. Results. The QL theory proposed here shows that the resulting transverse waves are right-hand polarized and have two consequences on the protons: (i) They reduce the relative drift between the beam and the core, but above all, (ii) they induce a strong perpendicular temperature anisotropy specific to the observed hammerhead ion beam. Moreover, the long-run QL results suggest that these hammerhead distributions are rather transitory states that are still subject to relaxation mechanisms, in which instabilities such as the one discussed here are very likely involved. This foundational work motivates future detailed studies using advanced methods. © The Authors 2024.
Uniform propagation of chaos for a dollar exchange econophysics model
(Publisher Cambridge University Press, 2024) Cao, Fei; Cortez, Roberto
We study the poor-biased model for money exchange introduced in Cao & Motsch ((2023) Kinet. Relat. Models 16(5), 764–794.): agents are being randomly picked at a rate proportional to their current wealth, and then the selected agent gives a dollar to another agent picked uniformly at random. Simulations of a stochastic system of finitely many agents as well as a rigorous analysis carried out in Cao & Motsch ((2023) Kinet. Relat. Models 16(5), 764–794.), Lanchier ((2017) J. Stat. Phys. 167(1), 160–172.) suggest that, when both the number of agents and time become large enough, the distribution of money among the agents converges to a Poisson distribution. In this manuscript, we establish a uniform-in-time propagation of chaos result as the number of agents goes to infinity, which justifies the validity of the mean-field deterministic infinite system of ordinary differential equations as an approximation of the underlying stochastic agent-based dynamics. © The Author(s), 2024.
Black carbon effects and seasonal isotope records in the Godwin‑Austen snowpack and K2 high-altitude camps
(Cambridge University Press, 0025) González-Santacruz, Nicolás; Fernandoy, Francisco; Goto-Azuma, Kumiko; Hirabayashi, Motohiro; Cordero, Raúl; Feron, Sarah; Faria, Sérgio Henrique
This study investigates black carbon (BC) concentrations in the seasonal snowpack on the Godwin-Austen Glacier and in surface snow at K2 Camps 1 and 2 (Karakoram Range), assessing their impact on snowmelt during the 2019 ablation season. Potential BC and moisture sources were identified through back-trajectory analysis and atmospheric reanalyses. Variations in water stable isotopes (δ18O and δ2H) in the snowpack were analysed to confirm its representativeness as a climatic record for the 2018–19 accumulation season. The average BC concentration in the snowpits (12 ng g-1) generated 66 mm w.e. (or 53 mm w.e. excluding the basal zone) of meltwater. Surface snow at K2 Camp 1 showed BC concentrations of 7 ng g-1, consistent with those on the snowpack surface, suggesting it may reflect local BC levels in late February 2019. In contrast, higher concentrations at K2 Camp 2 (26 ng g-1) were potentially linked to expedition activities. © 2025 Cambridge University Press. All rights reserved.
The fast rise of the unusual type IIL/IIb SN 2018ivc
(EDP Sciences, 0024-12) Reguitti A; Dastidar R.; Pignata G; Maeda K.; Moriya T.J.; Kuncarayakti H.; Rodríguez Ó; Bersten M.; Anderson J.P.; Charalampopoulos P.; Fraser M; Gromadzki M.
We present an analysis of the photometric and spectroscopic dataset of the type II supernova (SN) 2018ivc in the nearby (10 Mpc) galaxy Messier 77. Thanks to our high-cadence data, we observed the SN rising very rapidly by nearly three magnitudes in five hours (or 18 mag d- 1). The r-band light curve presents four distinct phases: the maximum light, which was reached in just one day, followed by a first, rapid linear decline and a short-duration plateau. Finally, the long, slower linear decline lasted for one year. Thanks to the ensuing radio re-brightening, we were able to detect SN 2018ivc four years after the explosion. The early spectra show a blue, nearly featureless continuum, but the spectra go on to evolve rapidly; after about ten days, a prominent Hα line starts to emerge, characterised by a peculiar profile. However, the spectra are heavily contaminated by emission lines from the host galaxy. The He I lines, namely λλ5876,7065, are also strong. In addition, strong absorption from the Na I doublet is evident and indicative of a non-negligible internal reddening. From its equivalent width, we derived a lower limit on the host reddening of AV ≲ 1.5 mag. From the Balmer decrement and a match of the B- V colour curve of SN 2018ivc to that of the comparison objects, we obtained a host reddening of AV ≲ 3.0 mag. The spectra are similar to those of SNe II, but with strong He lines. Given the peculiar light curve and spectral features, we suggest SN 2018ivc could be a transitional object between the type IIL and type IIb SNe classes. In addition, we found signs of an interaction with the circum-stellar medium (CSM) in the light curve, also making SN 2018ivc an interacting event. Finally, we modelled the early multi-band light curves and photospheric velocity of SN 2018ivc to estimate the physical parameters of the explosion and CSM. © The Authors 2024.
The Milky Way accretion history compared to cosmological simulations: From bulge formation to dwarf galaxy infall
(EDP Sciences, 0024-12) Hammer F; Jiao Y.J.; Mamon G.A; Yang Y.B; Akib I.; Amram P.; Wang H.F.; Wang J.L; Chemin L.
Galactic halos are known to grow hierarchically, inside out. This implies a correlation between the infall lookback time of satellites and their binding energy. Cosmological simulations predict a linear relation between the infall lookback time and the logarithm of the binding energy, with a small scatter. Gaia measurements of the bulk proper motions of globular clusters and dwarf satellites of the Milky Way are sufficiently accurate to establish the kinetic energies of these systems. Assuming the gravitational potential of the Milky Way, we can deduce the binding energies of the dwarf satellites and those of the galaxies that were previously accreted by the Milky Way. This can be compared to cosmological simulations for the first time. The relation of the infall lookback time versus binding energy we found in a cosmological simulation matches that for the early accretion events when the simulated total Milky Way mass within 21 kpc was rescaled to 2 1011 M. This agrees well with previous estimates from globular cluster kinematics and from the rotation curve. However, the vast majority of the dwarf galaxies are clear outliers to this rescaled relation, unless they are very recent infallers. In other words, the very low binding energies of most dwarf galaxies compared to Sgr and previous accreted galaxies suggests that most of them were accreted much later than 8 or even 5 Gyr ago. We also found that the subhalo systems in some cosmological simulations are too dynamically hot when they are compared to identified Milky Way substructures. This leads to an overestimated impact of satellites on the Galaxy rotation curve. © 2024 EDP Sciences. All rights reserved.
Fermion dark matter in the vector scotogenic model: a survey of signatures
(Springer Nature, 0024-12) Areyuna, Paulo C; Zamora-Saa, Jilberto; Zerwekh, Alfonso R.
In this work, we have studied the vector scotogenic model in the context of the dark matter problem. Due to unitarity considerations, we have focused on the scenario with fermion dark matter, finding out that co-annihilations play a fundamental role in achieving dark matter relic abundance. Moreover, the coannihilation effects allow to separate the parameter space into two regions with different phenomenology. In addition, we have studied the detection prospects of these regions separately, focusing on signatures that can appear in lepton flavor violating decays, indirect and direct searches, and the production of these new particles at collider facilities. © The Author(s) 2024.
Modified Heisenberg Commutation Relations and the Infinite-Square Well Potential: Some Simple Consequences
(Multidisciplinary Digital Publishing Institute (MDPI), 0024-10) González, Mauricio Contreras; Herrera, Roberto Ortiz; Gonzalez, José Mauricio
We explore some consequences of modifying the usual Heisenberg commutation relations of two simple systems: first, the one-dimensional quantum system given by the infinite square-well potential, and second, the case of a gas of N non-interacting particles in a box of volume V, which permit obtaining analytical solutions. We analyse two possible cases of modified Heisenberg commutation relations: one with a linear and non-linear dependence on the position and another with a linear and quadratic dependence on the momentum. We determine the eigenfunctions, probability densities, and energy eigenvalues for the one-dimensional square well for both deformation cases. For linear and non-linear x deformation dependence, the wave functions and energy levels change substantially when the weight factor associated with the modification term increases. Here, the energy levels are rescaled homogeneously. Instead, for linear and quadratic momentum p deformation dependence, the changes in the energy spectrum depend on the energy level. However, the probability densities are the same as those without any modification. For the non-interacting gas, the position deformation implies that the ideal gas state equation is modified, acquiring the form of a virial expansion in the volume, whereas the internal energy is unchanged. Instead, the ideal gas state equation remains unchanged at the lowest order in (Formula presented.) for the momentum modification case. However, the temperature modifies the internal energy at the lowest order in (Formula presented.). Thus, this study indicates that gravity could generate forces on particles by modifying the Heisenberg commutation relations. Therefore, gravitation could be the cause of the other three forces of nature. © 2024 by the authors.
Measurement of the muon flux at the SND@LHC experiment
(Institute for Ionics, 2024-01) Albanese, R.; Alexandrov, A.; Alicante, F.; Anokhina, A.; Asada, T.; Battilana, C.; Bay, A.; Betancourt, C.; Bick, D.; Biswas, R.; Castro, A. Blanco; Boccia, V.; Bogomilov, M.; Bonacorsi, D.; Bonivento, W.M.; Bordalo, P.; Boyarsky, A.; Buontempo, S.; Campanelli, M.; Camporesi, T.; Canale, V.; Castro, A.; Centanni, D.; Cerutti, F.; Chernyavskiy, M.; Choi, K.-Y.; Cholak, S.; Cindolo, F.; Climescu, M.; Conaboy, A.P.; Dallavalle, G.M.; Davino, D.; de Bryas, P.T.; De Lellis, G.; De Magistris, M.; De Roeck, A.; De Rújula, A.; De Serio, M.; De Simone, D.; Crescenzo, A. Di; Donà, R.; Durhan, O.; Fabbri, F.; Fedotovs, F.; Ferrillo, M.; Ferro-Luzzi, M.; Fini, R.A.; Fiorillo, A.; Fresa, R.; Funk, W.; Walls, F. M. Garay; Golovatiuk, A.; Golutvin, A.; Graverini, E.; Guler, A.M.; Guliaeva, V.; Haefeli, G.J.; Hagner, C.; Herrera, J. C. Helo; van Herwijnen, E.; Iengo, P.; Ilieva, S.; Infantino, A.; Iuliano, A.; Jacobsson, R.; Kamiscioglu, C.; Kauniskangas, A.M.; Khalikov, E.; Kim, S.H.; Kim, Y.G.; Klioutchnikov, G.; Komatsu, M.; Konovalova, N.; Kuleshov, S.; Lacker, H.M.; Lantwin, O.; Manghi, F. Lasagni; Lauria, A.; Lee, K.Y.; Lee, K.S.; Meo, S. Lo; Loschiavo, V.P.; Marcellini, S.; Margiotta, A.; Mascellani, A.; Miano, A.; Mikulenko, A.; Montesi, M.C.; Navarria, F.L.; Ogawa, S.; Okateva, N.; Ovchynnikov, M.; Paggi, G.; Park, B.D.; Pastore, A.; Perrotta, A.; Podgrudkov, D.; Polukhina, N.; Prota, A.; Quercia, A.; Ramos, S.; Reghunath, A.; Roganova, T.; Ronchetti, F.; Rovelli, T.; Ruchayskiy, O.; Ruf, T.; Gilarte, M. Sabate; Sadykov, Z.; Samoilov, M.; Scalera, V.; Schmidt-Parzefall, W.; Schneider, O.; Sekhniaidze, G.; Serra, N.; Shaposhnikov, M.; Shevchenko, V.; Shchedrina, T.; Shchutska, L.; Shibuya, H.; Simone, S.; Siroli, G.P.; Sirri, G.; Soares, G.; Sohn, J.Y.; Sandoval, O. J. Soto; Spurio, M.; Starkov, N.; Timiryasov, I.; Tioukov, V.; Tramontano, F.; Trippl, C.; Ursov, E.; Ustyuzhanin, A.; Vankova-Kirilova, G.; Verguilov, V.; Leonardo, N. Viegas Guerreiro; Vilela, C.; Visone, C.; Wanke, R.; Yaman E.; Yazici, C.; Yoon, C.S.; Zaffaroni, E.; Saa, J. Zamora
The Scattering and Neutrino Detector at the LHC (SND@LHC) started taking data at the beginning of Run 3 of the LHC. The experiment is designed to perform measurements with neutrinos produced in proton-proton collisions at the LHC in an energy range between 100 GeV and 1 TeV. It covers a previously unexplored pseudo-rapidity range of 7.2 < η< 8.4 . The detector is located 480 m downstream of the ATLAS interaction point in the TI18 tunnel. It comprises a veto system, a target consisting of tungsten plates interleaved with nuclear emulsion and scintillating fiber (SciFi) trackers, followed by a muon detector (UpStream, US and DownStream, DS). In this article we report the measurement of the muon flux in three subdetectors: the emulsion, the SciFi trackers and the DownStream Muon detector. The muon flux per integrated luminosity through an 18 × 18 cm 2 area in the emulsion is: 1.5±0.1(stat)×104fb/cm2. The muon flux per integrated luminosity through a 31 × 31 cm 2 area in the centre of the SciFi is: 2.06±0.01(stat)±0.12(sys)×104fb/cm2 The muon flux per integrated luminosity through a 52 × 52 cm 2 area in the centre of the downstream muon system is: 2.35±0.01(stat)±0.10(sys)×104fb/cm2 The total relative uncertainty of the measurements by the electronic detectors is 6 % for the SciFi and 4 % for the DS measurement. The Monte Carlo simulation prediction of these fluxes is 20–25 % lower than the measured values. © 2024, The Author(s).

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