A
bstract
Abelian U(1) gauge group extensions of the Standard Model represent one of the most minimal approaches to solve some of the most urgent particle physics questions and provide a rich ...phenomenology in various experimental searches. In this work, we focus on baryophilic vector mediator models in the MeV-to-GeV mass range and, in particular, present, for the first time, gauge vector field decays into almost arbitrary hadronic final states. Using only very little theoretical approximations, we rigorously follow the vector meson dominance theory in our calculations. We study the effect on the total and partial decay widths, the branching ratios, and not least on the present (future) experimental limits (reach) on (for) the mass and couplings of light vector particles in different models. We compare our results to current results in the literature. Our calculations are publicly available in a python package to compute various vector particle decay quantities in order to describe leptonic as well as hadronic decay signatures for experimental searches.
GeV-scale dark matter is an increasingly attractive target for
direct detection, indirect detection, and collider searches. Its
annihilation into hadronic final states produces a challenging zoo
of ...light hadronic resonances. We update Herwig7 to study
the photon and positron spectra from annihilation through a vector
mediator. It covers dark matter masses between 250 MeV and 5 GeV
and includes an error estimate.
B+L violation at colliders and new physics Cerdeño, David G.; Reimitz, Peter; Sakurai, Kazuki ...
The journal of high energy physics,
04/2018, Letnik:
2018, Številka:
4
Journal Article
Recenzirano
Odprti dostop
A
bstract
Chiral electroweak anomalies predict baryon (
B
) and lepton (
L
) violating fermion interactions, which can be dressed with large numbers of Higgs and gauge bosons. The estimation of the ...total
B
+
L
-violating rate from an initial two-particle state — potentially observable at colliders — has been the subject of an intense discussion, mainly centered on the resummation of boson emission, which is believed to contribute to the cross-section with an exponential function of the energy, yet with an exponent (the “holy-grail” function) which is not fully known in the energy range of interest. In this article we focus instead on the effect of fermions beyond the Standard-Model (SM) in the polynomial contributions to the rate. It is shown that
B
+
L
processes involving the new fermions have a polynomial contribution that can be several orders of magnitude greater than in the SM, for high centre-of-mass energies and light enough masses. We also present calculations that hint at a simple dependence of the holy grail function on the heavy fermion masses. Thus, if anomalous
B
+
L
violating interactions are ever detected at high-energy colliders, they could be associated with new physics.
We systematically study models with light scalar and pseudoscalar
dark matter candidates and their potential signals at the
LHC. First, we derive cosmological bounds on models with the
Standard Model ...Higgs mediator and with a new weak-scale
mediator. Next, we study two processes inspired by the indirect and
direct detection process topologies, now happening inside the LHC
detectors. We find that LHC can observe very light dark matter over
a huge mass range if it is produced in mediator decays and
then scatters with the detector material to generate jets in the
nuclear recoil.
Abstract
We present a new open-source package,
Hazma 2
, that computes accurate spectra relevant for indirect dark matter searches for photon, neutrino, and positron production from vector-mediated ...dark matter annihilation and for spin-one dark matter decay. The tool bridges across the regimes of validity of two state of the art codes:
Hazma 1
, which provides an accurate description below hadronic resonances up to center-of-mass energies around 250 MeV, and
Herwig4DM
, which is based on vector meson dominance and measured form factors, and accurate well into the few GeV range. The applicability of the combined code extends to approximately 1.5 GeV, above which the number of final state hadrons off of which we individually compute the photon, neutrino, and positron yield grows exceedingly rapidly. We provide example branching ratios, particle spectra and conservative observational constraints from existing gamma-ray data for the well-motivated cases of decaying dark photon dark matter and vector-mediated fermionic dark matter annihilation. Finally, we compare our results to other existing codes at the boundaries of their respective ranges of applicability.
Hazma 2
is freely available on GitHub at
https://github.com/LoganAMorrison/Hazma
.
Measuring the top Yukawa coupling at 100 TeV Mangano, Michelangelo L; Plehn, Tilman; Reimitz, Peter ...
Journal of physics. G, Nuclear and particle physics,
03/2016, Letnik:
43, Številka:
3
Journal Article
Recenzirano
Odprti dostop
We propose a measurement of the top Yukawa coupling at a 100 TeV hadron collider, based on boosted Higgs and top decays. We find that the top Yukawa coupling can be measured to 1%, with excellent ...handles for reducing systematic and theoretical uncertainties, both from side bands and from ratios.
We perform a complete study of the electroweak precision observables and electroweak gauge boson pair production in terms of the Standard Model effective field theory up to O ( 1/ Λ 4 ) under the ...assumption of universal C and P conserving new physics. We show that the analysis of data from those two sectors allows us to obtain closed constraints in the relevant parameter space in this scenario. In particular, we find that the Large Hadron Collider data can independently constrain the Wilson coefficients of the dimension-six and -eight operators directly contributing to the triple gauge boson vertices. Our results show that the impact of dimension-eight operators in the study of triple gauge couplings is small.
With its enormous number of produced neutrinos the LHC is a prime facility to study the behaviour of high-energy neutrinos. In this paper we propose a novel search strategy for identifying neutrino ...scattering via displaced appearing jets in the high granularity calorimeter (HGCAL) of the CMS endcap in the high luminosity run of the LHC. We demonstrate in a cut-and-count based analysis how the enormous hadronic background can be reduced while keeping most of the neutrino signal. This paper serves as a proof-of-principle study to illustrate the feasibility of the first direct observation of high-energetic neutrinos coming from \(W\) decays.
We present a new open-source package, Hazma 2, that computes accurate spectra relevant for indirect dark matter searches for photon, neutrino, and positron production from vector-mediated dark matter ...annihilation and for spin-one dark matter decay. The tool bridges across the regimes of validity of two state of the art codes: Hazma 1, which provides an accurate description below hadronic resonances up to center-of-mass energies around 250 MeV, and HERWIG4DM, which is based on vector meson dominance and measured form factors, and accurate well into the few GeV range. The applicability of the combined code extends to approximately 1.5 GeV, above which the number of final state hadrons off of which we individually compute the photon, neutrino, and positron yield grows exceedingly rapidly. We provide example branching ratios, particle spectra and conservative observational constraints from existing gamma-ray data for the well-motivated cases of decaying dark photon dark matter and vector-mediated fermionic dark matter annihilation. Finally, we compare our results to other existing codes at the boundaries of their respective ranges of applicability. Hazma 2 is freely available on GitHub.
Abelian U(1) gauge group extensions of the Standard Model represent one of the most minimal approaches to solve some of the most urgent particle physics questions and provide a rich phenomenology in ...various experimental searches. In this work, we focus on baryophilic vector mediator models in the MeV-to-GeV mass range and, in particular, present, for the first time, gauge vector field decays into almost arbitrary hadronic final states. Using only very little theoretical approximations, we rigorously follow the vector meson dominance theory in our calculations. We study the effect on the total and partial decay widths, the branching ratios, and not least on the present (future) experimental limits (reach) on (for) the mass and couplings of light vector particles in different models. We compare our results to current results in the literature. Our calculations are publicly available in a python package to compute various vector particle decay quantities in order to describe leptonic as well as hadronic decay signatures for experimental searches.
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