326 research outputs found
When gravity meets philosophy again: the Gravitas project
Gravity is, by far, one of the scientific themes that have most piqued the
curiosity of scientists and philosophers over the centuries. The history of
science tells us that when the creative effort of physicists and philosophers
to solve the main puzzles of the understanding of our universe met, a new
conceptual revolution has started. However, since Einstein's relativistic
theories and the subsequent advent of quantum mechanics, physicists and
philosophers have taken different paths, both kidnapped by the intrinsic
conceptual and mathematical difficulties inherited by their studies. Is it
possible to restore a unitary vision of knowledge, overcoming the
scientific-humanistic dichotomy that has established itself over time? The
answer is certainly not trivial, but we can start from school to experience a
new vision of a unified knowledge. From this need, the Gravitas project has
born. Gravitas is a multidisciplinary outreach and educational program devoted
to high school students (17-19 years old) that mixes contemporary physics and
the philosophy of science. Coordinated by the Cagliari Section of the National
Institute of Nuclear Physics, in Italy, Gravitas has started on December 2021
with an unconventional online format: two researchers coming from different
fields of research meet a moderator and informally discuss about gravity and
related phenomena. The public can chat and indirectly interact with them during
the YouTube live. The project involved about 250 students from 16 high schools
in Sardinia, Italy. Students should also create posts thought for social media
whose content is based on the seminars they attended during the project. We
present the project and discuss its possible outcomings concerning the
introduction of a multidisciplinary approach in teaching physics, philosophy,
and the history of contemporary physics in high schools.Comment: To appear in Proceedings of ICHEP 2022 Conference, 6 pages, 8
figures. An extended version of the abstract appears in the pape
Spin Physics at e^+e^- Colliders
A large number of measurements with polarized beams and/or spin analysis of
final state particles has been performed at the e^+e^- colliders LEP and SLC,
providing important information on the dynamics of high energy interactions. In
this paper three subjects, for which the role of spin studies was particularly
relevant, will be covered: the measurements of the electroweak couplings, the
study of fragmentation dynamics and the search for physics beyond the Standard
Model.Comment: 11 pages, Invited talk given at the International Workshop on
Symmetry and Spin - Prague, Czech Republic, August 30 - September 5, 199
Dark sectors 2016 Workshop: community report
This report, based on the Dark Sectors workshop at SLAC in April 2016,
summarizes the scientific importance of searches for dark sector dark matter
and forces at masses beneath the weak-scale, the status of this broad
international field, the important milestones motivating future exploration,
and promising experimental opportunities to reach these milestones over the
next 5-10 years
US Cosmic Visions: New Ideas in Dark Matter 2017: Community Report
This white paper summarizes the workshop "U.S. Cosmic Visions: New Ideas in
Dark Matter" held at University of Maryland on March 23-25, 2017.Comment: 102 pages + reference
Association between age of cannabis initiation and gray matter covariance networks in recent onset psychosis
Cannabis use during adolescence is associated with an increased risk of developing psychosis. According to a current hypothesis, this results from detrimental effects of early cannabis use on brain maturation during this vulnerable period. However, studies investigating the interaction between early cannabis use and brain structural alterations hitherto reported inconclusive findings. We investigated effects of age of cannabis initiation on psychosis using data from the multicentric Personalized Prognostic Tools for Early Psychosis Management (PRONIA) and the Cannabis Induced Psychosis (CIP) studies, yielding a total sample of 102 clinically-relevant cannabis users with recent onset psychosis. GM covariance underlies shared maturational processes. Therefore, we performed source-based morphometry analysis with spatial constraints on structural brain networks showing significant alterations in schizophrenia in a previous multisite study, thus testing associations of these networks with the age of cannabis initiation and with confounding factors. Earlier cannabis initiation was associated with more severe positive symptoms in our cohort. Greater gray matter volume (GMV) in the previously identified cerebellar schizophrenia-related network had a significant association with early cannabis use, independent of several possibly confounding factors. Moreover, GMV in the cerebellar network was associated with lower volume in another network previously associated with schizophrenia, comprising the insula, superior temporal, and inferior frontal gyrus. These findings are in line with previous investigations in healthy cannabis users, and suggest that early initiation of cannabis perturbs the developmental trajectory of certain structural brain networks in a manner imparting risk for psychosis later in life
Measurement of inclusive production in hadronic decays
An analysis is presented of inclusive \pi^0 production in Z^0 decays measured with the DELPHI detector. At low energies, \pi^0 decays are reconstructed by \linebreak using pairs of converted photons and combinations of converted photons and photons reconstructed in the barrel electromagnetic calorimeter (HPC). At high energies (up to x_p = 2 \cdot p_{\pi}/\sqrt{s} = 0.75) the excellent granularity of the HPC is exploited to search for two-photon substructures in single showers. The inclusive differential cross section is measured as a function of energy for {q\overline q} and {b \bar b} events. The number of \pi^0's per hadronic Z^0 event is N(\pi^0)/ Z_{had}^0 = 9.2 \pm 0.2 \mbox{(stat)} \pm 1.0 \mbox{(syst)} and for {b \bar b}~events the number of \pi^0's is {\mathrm N(\pi^0)/ b \overline b} = 10.1 \pm 0.4 \mbox{(stat)} \pm 1.1 \mbox{(syst)} . The ratio of the number of \pi^0's in b \overline b events to hadronic Z^0 events is less affected by the systematic errors and is found to be 1.09 \pm 0.05 \pm 0.01. The measured \pi^0 cross sections are compared with the predictions of different parton shower models. For hadronic events, the peak position in the \mathrm \xi_p = \ln(1/x_p) distribution is \xi_p^{\star} = 3.90^{+0.24}_{-0.14}. The average number of \pi^0's from the decay of primary \mathrm B hadrons is found to be {\mathrm N} (B \rightarrow \pi^0 \, X)/\mbox{B hadron} = 2.78 \pm 0.15 \mbox{(stat)} \pm 0.60 \mbox{(syst)}
Search for Neutral Heavy Leptons Produced in Z Decays
Weak isosinglet Neutral Heavy Leptons () have been searched for using data collected by the DELPHI detector corresponding to hadronic~Z decays at LEP1. Four separate searches have been performed, for short-lived production giving monojet or acollinear jet topologies, and for long-lived giving detectable secondary vertices or calorimeter clusters. No indication of the existence of these particles has been found, leading to an upper limit for the branching ratio Z of about at 95\% confidence level for masses between 3.5 and 50 GeV/. Outside this range the limit weakens rapidly with the mass. %Special emphasis has been given to the search for monojet--like topologies. One event %has passed the selection, in agreement with the expectation from the reaction: %. The results are also interpreted in terms of limits for the single production of excited neutrinos
Search for new phenomena using single photon events in the DELPHI detector at LEP
Data are presented on the reaction \epem~\into~\gamma + no other detected particle at center-of-mass energies, \sqs = 89.48 GeV, 91.26 GeV and 93.08 GeV. The cross section for this reaction is related directly to the number of light neutrino generations which couple to the \zz boson, and to several other phenomena such as excited neutrinos, the production of an invisible `X' particle, a possible magnetic moment of the tau neutrino, and neutral monojets. Based on the observed number of single photon events, the number of light neutrinos which couple to the \zz is measured to be N_\nu = 3.15 \pm 0.34. No evidence is found for anomalous production of energetic single photons, and upper limits at the 95\% confidence level are determined for excited neutrino production (BR < 4-9 \times 10^{-6}), production of an invisible `X' particle (\sigma < 0.1 pb), and the magnetic moment of the tau neutrino (< 5.2 \times 10^{-6} \mu_B). No event with the topology of a neutral monojet is found, and this corresponds to the limit \sigma < 0.044/\epsilon pb at the 95\% confidence level, where \epsilon is the unknown overall monojet detection efficiency
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