575 research outputs found
NA62 sensitivity to heavy neutral leptons in the low scale seesaw model
The sensitivity of beam dump experiments to heavy neutral leptons depends on
the relative strength of their couplings to individual lepton flavours in the
Standard Model. We study the impact of present neutrino oscillation data on
these couplings in the minimal type I seesaw model and find that it
significantly constrains the allowed heavy neutrino flavour mixing patterns. We
estimate the effect that the DUNE experiment will have on these predictions. We
then discuss implication that this has for the sensitivity of the NA62
experiment when operated in the beam dump mode and provide sensitivity
estimates for different benchmark scenarios. We find that the sensitivity can
vary by almost two orders of magnitude for general choices of the model
parameters, but depends only weakly on the flavour mixing pattern within the
parameter range that is preferred by neutrino oscillation data.Comment: 29 pages, 8 figures, 3 tables, version accepted by JHE
Gene expression changes of single skeletal muscle fibers in response to modulation of the mitochondrial calcium uniporter (MCU)
The mitochondrial calcium uniporter (MCU) gene codifies for the inner mitochondrial membrane (IMM) channel responsible for mitochondrial Ca2 + uptake. Cytosolic Ca2 + transients are involved in sarcomere contraction through cycles of release and storage in the sarcoplasmic reticulum. In addition cytosolic Ca2 + regulates various signaling cascades that eventually lead to gene expression reprogramming. Mitochondria are strategically placed in close contact with the ER/SR, thus cytosolic Ca2 + transients elicit large increases in the [Ca2 +] of the mitochondrial matrix ([Ca2 +]mt). Mitochondrial Ca2 + uptake regulates energy production and cell survival. In addition, we recently showed that MCU-dependent mitochondrial Ca2 + uptake controls skeletal muscle trophism. In the same report, we dissected the effects of MCU-dependent mitochondrial Ca2 + uptake on gene expression through microarray gene expression analysis upon modulation of MCU expression by in vivo AAV infection. Analyses were performed on single skeletal muscle fibers at two time points (7 and 14 days post-AAV injection). Raw and normalized data are available on the GEO database (http://www.ncbi.nlm.nih.gov/geo/) (GSE60931)
Perspectives to find heavy neutrinos with NA62
The sensitivity of beam dump experiments to heavy neutrinos depends on the
relative size of their mixings with the lepton flavours in the Standard Model.
We study the impact of present neutrino oscillation data on these mixing angles
in the minimal type I seesaw model. We find that current data significantly
constrains the allowed heavy neutrino flavour mixing patterns. Based on this,
we discuss the implications for the sensitivity of the NA62 experiment to heavy
neutrinos when operated in the beam dump mode. We find that NA62 is currently
the most sensitive experiment in the world for heavy neutrino masses between
that of the kaon and the -mesons. The sensitivity can vary by almost two
orders of magnitude if the heavy neutrinos exclusively couple to the tau
flavour, but depends only comparably weakly on the flavour mixing pattern
within the parameter range preferred by light neutrino oscillation data.Comment: Contribution to the proceedings of the 53rd Rencontres de Moriond on
Electroweak Interactions and Unified Theories (2018). 6 pages, 2 figure
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
Feebly-Interacting Particles:FIPs 2020 Workshop Report
With the establishment and maturation of the experimental programs searching
for new physics with sizeable couplings at the LHC, there is an increasing
interest in the broader particle and astrophysics community for exploring the
physics of light and feebly-interacting particles as a paradigm complementary
to a New Physics sector at the TeV scale and beyond. FIPs 2020 has been the
first workshop fully dedicated to the physics of feebly-interacting particles
and was held virtually from 31 August to 4 September 2020. The workshop has
gathered together experts from collider, beam dump, fixed target experiments,
as well as from astrophysics, axions/ALPs searches, current/future neutrino
experiments, and dark matter direct detection communities to discuss progress
in experimental searches and underlying theory models for FIPs physics, and to
enhance the cross-fertilisation across different fields. FIPs 2020 has been
complemented by the topical workshop "Physics Beyond Colliders meets theory",
held at CERN from 7 June to 9 June 2020. This document presents the summary of
the talks presented at the workshops and the outcome of the subsequent
discussions held immediately after. It aims to provide a clear picture of this
blooming field and proposes a few recommendations for the next round of
experimental results.Comment: 240 pages, 71 figure
Search for heavy neutral lepton production in K+ decays
A search for heavy neutral lepton production in K + decays using a data sample collected with a minimum
bias trigger by the NA62 experiment at CERN in 2015 is reported. Upper limits at the 10â7 to 10â6 level
are established on the elements of the extended neutrino mixing matrix |Ue4|
2 and |UΌ4|
2 for heavy
neutral lepton mass in the ranges 170â448 MeV/c2 and 250â373 MeV/c2, respectively. This improves on
the previous limits from HNL production searches over the whole mass range considered for |Ue4|2 and
above 300 MeV/c2 for |UΌ4|2
Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires
The production of tt⟠, W+bb⟠and W+cc⟠is studied in the forward region of protonâproton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fbâ1 . The W bosons are reconstructed in the decays WââÎœ , where â denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of , and is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 0.02 \mbox{fb}^{-1}. The bosons are reconstructed in the decays , where denotes muon or electron, while the and quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions
Multidifferential study of identified charged hadron distributions in -tagged jets in proton-proton collisions at 13 TeV
Jet fragmentation functions are measured for the first time in proton-proton
collisions for charged pions, kaons, and protons within jets recoiling against
a boson. The charged-hadron distributions are studied longitudinally and
transversely to the jet direction for jets with transverse momentum 20 GeV and in the pseudorapidity range . The
data sample was collected with the LHCb experiment at a center-of-mass energy
of 13 TeV, corresponding to an integrated luminosity of 1.64 fb. Triple
differential distributions as a function of the hadron longitudinal momentum
fraction, hadron transverse momentum, and jet transverse momentum are also
measured for the first time. This helps constrain transverse-momentum-dependent
fragmentation functions. Differences in the shapes and magnitudes of the
measured distributions for the different hadron species provide insights into
the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any
supplementary material and additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb
public pages
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