2,075 research outputs found

    Search for heavy neutral leptons using tau lepton decays at BaBar

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    This article presents a model-independent search for an additional, mostly sterile, heavy neutral lepton (HNL), that is capable of mixing with the Standard Model τ neutrino with a mixing strength of |Uτ4|2, corresponding to the absolute square of the extended Pontecorvo-Maki-Nakagawa-Sakata matrix element. Data from the BABAR experiment, with a total integrated luminosity of 424 fb-1, are analyzed using a kinematic approach that makes no assumptions on the model behind the origins of the HNL, its lifetime or decay modes. No significant signal is found. Upper limits on |Uτ4|2 at the 95% confidence level, depend on the HNL mass hypothesis and vary from 2.31×10-2 to 5.04×10-6 (with all uncertainties considered), across the mass range 100<1300 MeV/c2; the more stringent limits being placed at higher masses

    Measurement of additional radiation in the initial-state-radiation processes <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>e</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>e</mml:mi><mml:mo>−</mml:mo></mml:msup><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mi>ÎŒ</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>ÎŒ</mml:mi><mml:mo>−</mml:mo></mml:msup><mml:mi>Îł</mml:mi></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>e</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>e</mml:mi><mml:mo>−</mml:mo></mml:msup><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mi>π</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>π</mml:mi><mml:mo>−</mml:mo></mml:msup><mml:mi>Îł</mml:mi></mml:math> at <i>BABAR</i>

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    A dedicated measurement of additional radiation in e+e-→Ό+ÎŒ-Îł and e+e-→π+π-Îł initial-state-radiation events is presented using the full BABAR data sample. For the first time results are presented at next-to- and next-to-next-to-leading order, with one and two additional photons, respectively, for radiation from the initial and final states. Comparison with predictions from phokhara and afkqed Monte Carlo generators is performed, revealing discrepancies in the one-photon rates and angular distributions for the former. This disagreement has a negligible effect on the BABAR measurement of the e+e-→π+π-(Îł) cross section, but could affect other measurements significantly. This study sheds a new light on the longstanding discrepancy in this channel that affects the theoretical prediction of hadronic vacuum polarization contributions to the muon magnetic moment anomaly

    Rare predicted loss-of-function variants of type I IFN immunity genes are associated with life-threatening COVID-19

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    BackgroundWe previously reported that impaired type I IFN activity, due to inborn errors of TLR3- and TLR7-dependent type I interferon (IFN) immunity or to autoantibodies against type I IFN, account for 15-20% of cases of life-threatening COVID-19 in unvaccinated patients. Therefore, the determinants of life-threatening COVID-19 remain to be identified in similar to 80% of cases.MethodsWe report here a genome-wide rare variant burden association analysis in 3269 unvaccinated patients with life-threatening COVID-19, and 1373 unvaccinated SARS-CoV-2-infected individuals without pneumonia. Among the 928 patients tested for autoantibodies against type I IFN, a quarter (234) were positive and were excluded.ResultsNo gene reached genome-wide significance. Under a recessive model, the most significant gene with at-risk variants was TLR7, with an OR of 27.68 (95%CI 1.5-528.7, P=1.1x10(-4)) for biochemically loss-of-function (bLOF) variants. We replicated the enrichment in rare predicted LOF (pLOF) variants at 13 influenza susceptibility loci involved in TLR3-dependent type I IFN immunity (OR=3.70[95%CI 1.3-8.2], P=2.1x10(-4)). This enrichment was further strengthened by (1) adding the recently reported TYK2 and TLR7 COVID-19 loci, particularly under a recessive model (OR=19.65[95%CI 2.1-2635.4], P=3.4x10(-3)), and (2) considering as pLOF branchpoint variants with potentially strong impacts on splicing among the 15 loci (OR=4.40[9%CI 2.3-8.4], P=7.7x10(-8)). Finally, the patients with pLOF/bLOF variants at these 15 loci were significantly younger (mean age [SD]=43.3 [20.3] years) than the other patients (56.0 [17.3] years; P=1.68x10(-5)).ConclusionsRare variants of TLR3- and TLR7-dependent type I IFN immunity genes can underlie life-threatening COVID-19, particularly with recessive inheritance, in patients under 60 years old

    Search for heavy neutral leptons using tau lepton decays at <i>BaBaR</i>

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    This article presents a model-independent search for an additional, mostly sterile, heavy neutral lepton (HNL), that is capable of mixing with the Standard Model τ neutrino with a mixing strength of |Uτ4|2, corresponding to the absolute square of the extended Pontecorvo-Maki-Nakagawa-Sakata matrix element. Data from the BABAR experiment, with a total integrated luminosity of 424 fb-1, are analyzed using a kinematic approach that makes no assumptions on the model behind the origins of the HNL, its lifetime or decay modes. No significant signal is found. Upper limits on |Uτ4|2 at the 95% confidence level, depend on the HNL mass hypothesis and vary from 2.31×10-2 to 5.04×10-6 (with all uncertainties considered), across the mass range 100<m4<1300 MeV/c2; the more stringent limits being placed at higher masses

    Precision e- beam polarimetry at an e+e- B factory using tau-pair events

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    We present a new technique, "tau polarimetry,"for measuring the longitudinal beam polarization present in an e+e- collider through the analysis of e+e-→τ+τ- events. By exploiting the sensitivity of τ decay kinematics to the longitudinal polarization of the beams, we demonstrate that the longitudinal polarization can be measured with a 3 per mil systematic uncertainty at the interaction point using a technique that is independent of spin and beam transport modeling. Using 424.2±1.8 fb-1 of BABAR data at s=10.58 GeV, the average longitudinal polarization of the PEP-II e+e- collider has been measured to be ⟹P

    CaractĂ©risation transdisciplinaire d'un aquifĂšre cĂŽtier complexe, pour une exploitation maitrisĂ©e et durable de sa ressource en eau en contexte mĂ©diterranĂ©en. Le projet DEM'EAUX ROUSSILLON. Communication orale (‱ connaissances scientifiques ; ‱ savoirs faire techniques)

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    International audiencePlus de 80 millions de m3 par an sont prĂ©levĂ©s dans les nappes de la plaine du Roussillon. Ce volume est d’abord destinĂ© Ă  l’alimentation en eau potable, dont la demande a connu une forte augmentation depuis les annĂ©es 1950 (doublement de population et dĂ©veloppement du tourisme sur le littoral), mais il contribue aussi Ă  l’irrigation des quelques 13 000 hectares. La plaine du Roussillon, qui s’étend sur 850 kmÂČ, est bordĂ©e par les PyrĂ©nĂ©es Ă  l’ouest, le massif des CorbiĂšres au nord et la MĂ©diterranĂ©e Ă  l’est. Entre les tempĂ©ratures Ă©levĂ©es (15°C en moyenne annuelle Ă  Perpignan) et la faible pluviomĂ©trie (700 mm/an), les situations de sĂ©cheresse ne sont pas rares et leur frĂ©quence et intensitĂ© risquent de s’accroĂźtre dans le futur avec l’augmentation de la tempĂ©rature projetĂ©e. Les ressources en eau souterraine de l’aquifĂšre seront ĂȘtre affectĂ©es, surtout les plus proches de la surface. Les besoins en eau pourraient aussi Ă©voluer (hausse potentielle de l’ordre de 15% des besoins pour l’irrigation (Ă  surfaces irriguĂ©es constantes) et augmentation des superficies Ă  irriguer). De plus, vu la faible altitude de son littoral, la plaine du Roussillon risque d’ĂȘtre touchĂ©e par la hausse du niveau marin, qui pourrait atteindre 1 m d’ici 2100. Une augmentation des submersions marines en seraient la consĂ©quence entrainant un risque de salinisation des eaux souterraines plus Ă©levĂ©. Le principal aquifĂšre de la zone, le « Plio-Quaternaire du Roussillon » est un multicouche datĂ© du PliocĂšne, de plus de 250 m d’épaisseur, constituĂ© de niveaux sableux sĂ©parĂ©s par des niveaux peu permĂ©ables et surmontĂ©s par des formations alluviales du Quaternaire. Depuis plus de 40 ans, cet aquifĂšre subit une baisse gĂ©nĂ©ralisĂ©e de son niveau de remplissage. Jusqu’oĂč s’étend le rĂ©servoir sous la mer et l’eau y est-elle douce? Quelles sont les interactions avec les aquifĂšres environnants et avec la mer ? Quels sont les risques d’intrusion saline dans le contexte d’élĂ©vation du niveau marin ? Comment vont Ă©voluer les besoins en eau, avec des Ă©pisodes de sĂ©cheresse potentiellement plus marquĂ©s Ă  l’avenir ? Comment utiliser au mieux les nouvelles technologies pour un outil de gestion en temps rĂ©el de la ressource ? Ces questions ont structurĂ© le projet Dem’Eaux Roussillon (2017-2021) qui a regroupĂ© prĂšs de dix partenaires de la rĂ©gion Occitanie (Ă©tablissements de recherche, bureaux d’étude et collectivitĂ©s). Les compĂ©tences mobilisĂ©es couvrent la gĂ©ologie, la gĂ©ophysique, la gĂ©ochimie, l’hydraulique, l’hydrologie, l’économie, l’optronique, l’instrumentation, l’imagerie spatiale et l’informatique. Son objectif Ă©tait de caractĂ©riser le comportement de la ressource en eau souterraine dans cet aquifĂšre, pour pouvoir se projeter sur sa situation future, dans le contexte du changement climatique, de l’élĂ©vation du niveau de la mer (risque d’intrusion saline) et de l’évolution des usages de l’eau. Les travaux rĂ©alisĂ©s ont permis de caractĂ©riser le rĂ©servoir gĂ©ologique de maniĂšre fine et en particulier l’extension sous-marine de cet aquifĂšre cĂŽtier. Une analyse de l’historique de la piĂ©zomĂ©trie Ă  l’échelle de la plaine sur les 50 derniĂšres annĂ©es permet de discuter des processus de drainance verticale Ă  l’Ɠuvre entre les diffĂ©rentes couches de l’aquifĂšre. Deux observatoires hydro-gĂ©ophysiques Ă  haute-rĂ©solution ont Ă©tĂ© mis sur pied, qui permettent de quantifier ces processus et d’amĂ©liorer la comprĂ©hension du phĂ©nomĂšne d’intrusion saline dans cet aquifĂšre. Un outil de concentration et de valorisation des donnĂ©es relatives Ă  la gestion de la ressource a enfin Ă©tĂ© construit et commence Ă  s’inscrire dans la durĂ©e sur le territoire. L’ensemble de rĂ©sultats obtenus dans le cadre de ce projet seront prĂ©sentĂ©s et discutĂ©s

    Study of the reactions e plus e- ? K+K-,r0,r0,r0, e+ e-?K0SK?,r?,r0,r0, and e plus e-? K0SK?,r?,r+,r- at center-of-mass energies from threshold to 4.5 GeV using initial-state radiation

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    We study the processes e+e-→K+K-π0π0π0Îł, KS0K±π?π0π0Îł, and KS0K±π?π+π-Îł in which an energetic photon is radiated from the initial state. The data were collected with the BABAR detector at the SLAC National Accelerator Laboratory. About 1200, 2600, and 6000 events, respectively, are selected from a data sample corresponding to an integrated luminosity of 469 fb-1. The invariant mass of the hadronic final state defines the effective e+e- center-of-mass energy. The center-of-mass energies range from threshold to 4.5 GeV. From the mass spectra, the first ever measurements of the e+e-→K+K-π0π0π0, e+e-→KS0K±π?π0π0, and e+e-→KS0K±π?π+π- cross sections are performed. The contributions from the intermediate states that include η, φ, ρ, K∗(892), and other resonances are presented. We observe the J/ψ and ψ(2S) in most of these final states and measure the corresponding branching fractions, many of them for the first time

    Search for BB Mesogenesis at BABAR

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    A new mechanism has been proposed to simultaneously explain the presence of dark matter and the matter-antimatter asymmetry in the universe. This scenario predicts exotic BB meson decays into a baryon and a dark sector anti-baryon (ψD\psi_D) with branching fractions accessible at BB factories. We present a search for B→ΛψDB \rightarrow \Lambda \psi_D decays using data collected by the BABARBABAR experiment at SLAC. This reaction is identified by fully reconstructing the accompanying BB meson and requiring the presence of a single Λ\Lambda baryon in the remaining particles. No significant signal is observed, and bounds on the B→ΛψDB \rightarrow \Lambda \psi_D branching fraction are derived in the range 0.13−5.2×10−50.13 - 5.2\times 10^{-5} for 1.0<mψD<4.21.0 < m_{\psi_D} < 4.2 GeV/c2c^{2}. These results set strong constraints on the parameter space allowed by the theory

    Croisées des chemins

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    Les croisements de rues comme de routes sont des lieux qui fixent certains types d’activitĂ©s en lien avec le voyage, avec le dĂ©placement sur des distances courtes ou longues, connues ou inconnues : s’arrĂȘter, choisir une direction, se prĂ©parer Ă  partir
 Ils sont aussi le lieu de rencontres, de relais, d’échanges de marchandise, d’offres de service
 Autant d’activitĂ©s (boutique, entrepĂŽt, atelier, hĂŽtellerie...) qui laissent Ă©galement des traces. Et au-delĂ  de ces aspects concrets, ou en lien avec eux, les croisements sont liĂ©s Ă  des croyances et des pratiques religieuses (autels, temples
) et/ou funĂ©raires (tombe, cĂ©notaphe, nĂ©cropole). Sur quels Ă©lĂ©ments se baser, en archĂ©ologie, pour identifier ces carrefours (topographie, bornes, raccords de voiries, types de trottoirs ou de bordures, signalisation
) ? Peut-on distinguer, par exemple, ceux qui marquent des limites sociales ou politiques, entre peuples, entre agglomĂ©rations, entre quartiers
 ? The crossroads of streets and roads are where certain types of activities related to travel take place, moving over short or long distances, known or unknown: stopping, choosing a direction, preparing to leave, etc. Crossroads also act as places to meet, effect handovers, exchange goods and offer services, and all of these activities leave their mark (e.g. shops, warehouses, workshops, hotels...). Beyond these concrete aspects, there are countless cases where crossroads are linked to religious beliefs and practices (e.g. altars, temples) and/or funerary practices (burial, cenotaph, necropolis). But what elements should archaeology use in order to identify these crossroads (e.g. topography, landmarks, road connections, types of pavements or kerbs, signs)? And can we distinguish, for example, those that mark social or political limits, between people, between settlements, between neighbourhoods, etc? Las encrucijadas de calles y caminos son lugares que fijan cierto tipo de actividades relacionadas con el viaje, el desplazamiento sobre distancias largas o cortas, conocidas o desconocidas: detenerse, elegir una direcciĂłn, prepararse a partir
 Las encrucijadas son tambiĂ©n lugares de encuentro, de relevo, de intercambios de mercancĂ­as, de ofertas de servicio
 un sinnĂșmero de actividades -tales como tiendas, almacenes, talleres, hostelerĂ­a- que dejan igualmente huellas. MĂĄs allĂĄ de estos aspectos concretos, son innumerables los casos donde las encrucijadas estĂĄn relacionadas con creencias y prĂĄcticas religiosas (altares, templos
) y/o funerarias (tumbas, cenotafios, necrĂłpolis). ÂżSobre quĂ© elementos debe basarse la arqueologĂ­a para identificar dichos cruces (topografĂ­a, hitos, empalmes de redes viales, tipos de aceras o de bordes, señalizaciĂłn y demĂĄs)? ÂżEs posible distinguir, por ejemplo, aquellos que marcan lĂ­mites sociales o polĂ­ticos entre pueblos, entre aglomeraciones, entre barrios, etcĂ©tera

    Study of the reactions e+ e- →K+ K- π0 π0 π0, e+ e- → KS0 K± π± π0 π0, and e+e- → KS0 K± π0 π+ π- at center-of-mass energies from threshold to 4.5 GeV using initial-state radiation

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    We study the processes e+e-→K+ K- π0 π0 π0 Îł, KS0 K± π± π0 π0 Îł, and KS0 K± π0 π+π-Îł in which an energetic photon is radiated from the initial state. The data were collected with the BABAR detector at the SLAC National Accelerator Laboratory. About 1200, 2600, and 6000 events, respectively, are selected from a data sample corresponding to an integrated luminosity of 469 fb-1. The invariant mass of the hadronic final state defines the effective e+e- center-of-mass energy. The center-of-mass energies range from threshold to 4.5 GeV. From the mass spectra, the first ever measurements of the e+e-→K+K-π0π0π0, e+e-→KS0K±π ± π0π0, and e+e-→KS0K±π0π+π- cross sections are performed. The contributions from the intermediate states that include η, φ, ρ, K∗(892), and other resonances are presented. We observe the J/ψ and ψ(2S) in most of these final states and measure the corresponding branching fractions, many of them for the first time
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