The leading-order contribution of a new boson to the muonic fine-structure anomaly, which refers to a discrepancy between the predicted transition energies and spectroscopic measurements of μ−90Zr, ...μ−120Sn, and μ−208Pb, is investigated. We consider bosons of scalar, vector, pseudoscalar, and pseudovector type. Spin-dependent couplings sourced by pseudoscalars or pseudovectors are disfavoured as solutions to the anomaly due to the nuclei in question having vanishing angular momentum. Spin-independent interactions resulting from scalar or vector exchange are also disfavoured because no parameter space exists to simultaneously fit different atomic states of the same nucleus. Therefore, we conclude that a ‘Beyond-the-Standard-Model’ resolution of the muonic fine-structure anomaly is generally disfavoured, and the first-order solution by a single new boson is excluded.
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2.
CheckMATE 2: From the model to the limit Dercks, Daniel; Desai, Nishita; Kim, Jong Soo ...
Computer physics communications,
December 2017, 2017-12-00, Volume:
221
Journal Article
Peer reviewed
Open access
We present the latest developments to the CheckMATE program that allows models of new physics to be easily tested against the recent LHC data. To achieve this goal, the core of CheckMATE now contains ...over 60 LHC analyses of which 12 are from the 13 TeV run. The main new feature is that CheckMATE 2 now integrates the Monte Carlo event generation via MadGraph5_aMC@NLO and Pythia 8. This allows users to go directly from a SLHA file or UFO model to the result of whether a model is allowed or not. In addition, the integration of the event generation leads to a significant increase in the speed of the program. Many other improvements have also been made, including the possibility to now combine signal regions to give a total likelihood for a model.
Program Title: CheckMATE
Program Files doi:http://dx.doi.org/10.17632/k4pnk5wrfm.1
Licensing provisions: GPLv3
Programming language: C++, Python
External routines/libraries: ROOT, Python, HepMC (optional) Pythia 8 (optional), Madgraph5_aMC@NLO (optional)
Subprograms used: Delphes
Nature of problem: The LHC experiments have performed a huge number of searches for new physics in the past few years. However the results can only be given for a few benchmark models out of the huge number that exist in the literature.
Solution method: CheckMATE is a program that automatically calculates limits for new physics models. The original version required the user to generate Monte Carlo events themselves before CheckMATE could be run but the new version now integrates this step. The simplest output of CheckMATE is whether the model is ruled out at 95% CLs or not. However, more complicated statistical metrics are also available, including the combination of many signal regions.
Restrictions: Only a subset of available experimental results have been implemented.
Additional comments:
•CheckMATE is built upon the tools and hard work of many people. If CheckMATE is used in your publication it is extremely important that all of the following citations are included, –Delphes 3 1.https://cp3.irmp.ucl.ac.be/projects/delphes–FastJet 2,3.http://fastjet.fr/–Anti-kt jet algorithm 4.–CLS prescription 5.–All experimental analyses that were used to set limits in the study and if the analysis was implemented by non- CheckMATE authors, the relevant implementation reference.–MadGraph5_aMC@NLO 6 if it is used to calculate the hard matrix element from within CheckMATE.https://launchpad.net/mg5amcnlo–Pythia8.2 7 if showering or matching is done from within CheckMATE.http://home.thep.lu.se/~torbjorn/Pythia.html–The Monte Carlo event generator that was used if .hepmc or .lhe files were generated externally.–In analyses that use the mT2 kinematical discriminant 8,9 we use the mt2_bisect library 10. We also include the MT2bℓ and MT2W derivatives 11.http://particle.physics.ucdavis.edu/hefti/projects/doku.php?id=wimpmasshttps://sites.google.com/a/ucdavis.edu/mass/–In analyses that use the MCT family of kinematical discriminants we use the MctLib library that includes the following variables, MCT 12, MCT corrected 13, MCT parallel and perpendicular 14.https://mctlib.hepforge.org/–In analyses that use topness variable we use the topness library 15.https://github.com/michaelgraesser/topness–Super-Razor 16 in analyses that use this variable.
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6 J. Alwall et al., JHEP 1407 (2014) 079 arXiv:1405.0301 hep-ph.
7 T. Sjöstrand et al., Comput. Phys. Commun. 191 (2015) 159 arXiv:1410.3012 hep-ph.
8 C. G. Lester and D. J. Summers, Phys. Lett. B 463 (1999) 99 hep-ph/9906349.
9 A. Barr, C. Lester and P. Stephens, J. Phys. G 29 (2003) 2343 hep-ph/0304226.
10 H. C. Cheng and Z. Han, JHEP 0812 (2008) 063 arXiv:0810.5178 hep-ph.
11 Y. Bai, H. C. Cheng, J. Gallicchio and J. Gu, JHEP 1207 (2012) 110 arXiv:1203.4813 hep-ph.
12 D. R. Tovey, JHEP 0804 (2008) 034 arXiv:0802.2879 hep-ph.
13 G. Polesello and D. R. Tovey, JHEP 1003 (2010) 030 arXiv:0910.0174 hep-ph.
14 K. T. Matchev and M. Park, Phys. Rev. Lett. 107 (2011) 061801 arXiv:0910.1584 hep-ph.
15 M. L. Graesser and J. Shelton, Phys. Rev. Lett. 111 (2013) no.12, 121802 arXiv:1212.4495 hep-ph.
16 M. R. Buckley, J. D. Lykken, C. Rogan and M. Spiropulu, Phys. Rev. D 89 (2014) no.5, 055020 arXiv:1310.4827 hep-ph.
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Neutrinos and collider physics Deppisch, Frank F; Bhupal Dev, P S; Pilaftsis, Apostolos
New journal of physics,
08/2015, Volume:
17, Issue:
7
Journal Article
Peer reviewed
Open access
We review the collider phenomenology of neutrino physics and the synergetic aspects at energy, intensity and cosmic frontiers to test the new physics behind the neutrino mass mechanism. In ...particular, we focus on seesaw models within the minimal setup as well as with extended gauge and/or Higgs sectors, and on supersymmetric neutrino mass models with seesaw mechanism and with R-parity violation. In the simplest type-I seesaw scenario with sterile neutrinos, we summarize and update the current experimental constraints on the sterile neutrino mass and its mixing with the active neutrinos. We also discuss the future experimental prospects of testing the seesaw mechanism at colliders and in related low-energy searches for rare processes, such as lepton flavor violation and neutrinoless double beta decay. The implications of the discovery of lepton number violation at the Large Hadron Collider for leptogenesis are also studied.
Neutrinoless double-beta decay is a forbidden, lepton-number-violating nuclear transition whose observation would have fundamental implications for neutrino physics, theories beyond the Standard ...Model, and cosmology. In this review, we summarize the theoretical progress to understand this process, the expectations and implications under various particle physics models, and the nuclear physics challenges that affect the precise predictions of the decay half-life. We also provide a synopsis of the current and future large-scale experiments that aim to discover this process in physically well-motivated half-life ranges.
We investigate the consequences of deviations from the Standard Model observed in b→sμμ transitions for flavour-changing neutral-current processes involving down-type quarks and neutrinos. We derive ...the relevant Wilson coefficients within an effective field theory approach respecting the SM gauge symmetry, including right-handed currents, a flavour structure based on approximate U(2) symmetry, and assuming only SM-like light neutrinos. We discuss correlations among B→K(⁎)νν¯ and K→πνν¯ branching ratios in the case of linear Minimal Flavour Violation and in a more general framework, highlighting in each case the role played by various New Physics scenarios proposed to explain b→sμμ deviations.
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This paper describes the physics case for a new fixed target facility at CERN SPS. The SHiP (search for hidden particles) experiment is intended to hunt for new physics in the largely unexplored ...domain of very weakly interacting particles with masses below the Fermi scale, inaccessible to the LHC experiments, and to study tau neutrino physics. The same proton beam setup can be used later to look for decays of tau-leptons with lepton flavour number non-conservation, τ→3μ and to search for weakly-interacting sub-GeV dark matter candidates. We discuss the evidence for physics beyond the standard model and describe interactions between new particles and four different portals-scalars, vectors, fermions or axion-like particles. We discuss motivations for different models, manifesting themselves via these interactions, and how they can be probed with the SHiP experiment and present several case studies. The prospects to search for relatively light SUSY and composite particles at SHiP are also discussed. We demonstrate that the SHiP experiment has a unique potential to discover new physics and can directly probe a number of solutions of beyond the standard model puzzles, such as neutrino masses, baryon asymmetry of the Universe, dark matter, and inflation.
This is a review paper about neutrino mass and mixing and flavour model building strategies based on discrete family symmetry. After a pedagogical introduction and overview of the whole of neutrino ...physics, we focus on the PMNS mixing matrix and the latest global fits following the Daya Bay and RENO experiments which measure the reactor angle. We then describe the simple bimaximal, tri-bimaximal and golden ratio patterns of lepton mixing and the deviations required for a non-zero reactor angle, with solar or atmospheric mixing sum rules resulting from charged lepton corrections or residual trimaximal mixing. The different types of see-saw mechanism are then reviewed as well as the sequential dominance mechanism. We then give a mini-review of finite group theory, which may be used as a discrete family symmetry broken by flavons either completely, or with different subgroups preserved in the neutrino and charged lepton sectors. These two approaches are then reviewed in detail in separate chapters including mechanisms for flavon vacuum alignment and different model building strategies that have been proposed to generate the reactor angle. We then briefly review grand unified theories (GUTs) and how they may be combined with discrete family symmetry to describe all quark and lepton masses and mixing. Finally, we discuss three model examples which combine an SU(5) GUT with the discrete family symmetries A4, S4 and Δ(96).
Neutrinos, being the only fermions in the Standard Model of Particle Physics that do not possess electromagnetic or color charges, have the unique opportunity to communicate with fermions outside the ...Standard Model through mass mixing. Such Standard Model-singlet fermions are generally referred to as “sterile neutrinos”. In this review article, we discuss the theoretical and experimental motivation for sterile neutrinos, as well as their phenomenological consequences. With the benefit of hindsight in 2020, we point out potentially viable and interesting ideas. We focus in particular on sterile neutrinos that are light enough to participate in neutrino oscillations, but we also comment on the benefits of introducing heavier sterile states. We discuss the phenomenology of eV-scale sterile neutrinos in terrestrial experiments and in cosmology, we survey the global data, and we highlight various intriguing anomalies. We also expose the severe tension that exists between different data sets and prevents a consistent interpretation of the global data in at least the simplest sterile neutrino models. We discuss non-minimal scenarios that may alleviate some of this tension. We briefly review the status of keV-scale sterile neutrinos as dark matter and the possibility of explaining the matter–antimatter asymmetry of the Universe through leptogenesis driven by yet heavier sterile neutrinos.
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This article presents a search for new resonances decaying into a Z or W boson and a 125 GeV Higgs boson h, and it targets the v (v) over barb (b) over bar, l(+)l(-) b (b) over bar, or l(+/-) vb (b) ...over bar final states, where l - e or mu, in proton-proton collisions at root s - 13 TeV. The data used correspond to a total integrated luminosity of 139 fb(-1) collected by the ATLAS detector during Run 2 of the LHC at CERN. The search is conducted by examining the reconstructed invariant or transverse mass distributions of Zh or Wh candidates for evidence of a localised excess in the mass range from 220 GeV to 5TeV. No significant excess is observed and 95% confidence-level upper limits between 1.3 pb and 0.3 fb are placed on the production cross section times branching fraction of neutral and charged spin-1 resonances and CP-odd scalar bosons. These limits are converted into constraints on the parameter space of the Heavy Vector Triplet model and the two-Higgs-doublet model.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We define a data exchange format for numerical values of Wilson coefficients of local operators parameterising low-energy effects of physics beyond the Standard Model. The format facilitates ...interfacing model-specific Wilson coefficient calculators, renormalisation group (RG) runners, and observable calculators. It is designed to be unambiguous (defining a non-redundant set of operators with fixed normalisation in each basis), extensible (allowing the addition of new EFTs or bases by the user), and robust (being based on industry standard file formats with parsers implemented in many programming languages). We have implemented the format for the Standard Model EFT (SMEFT) and for the weak effective theory (WET) below the electroweak scale and have added interfaces to a number of public codes dealing with SMEFT or WET. We also provide command-line utilities and a Python module for convenient manipulation of WCxf files, including translation between different bases and matching from SMEFT to WET.
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