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.
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.
CheckMATE 2: From the model to the limit Dercks, Daniel; Desai, Nishita; Kim, Jong Soo ...
Computer physics communications,
December 2017, 2017-12-00, Letnik:
221
Journal Article
Recenzirano
Odprti dostop
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.
1 J. de Favereau et al. DELPHES 3 Collaboration, JHEP 1402 (2014) 057 arXiv:1307.6346 hep-ex.
2 M. Cacciari, G. P. Salam and G. Soyez, Eur. Phys. J. C 72 (2012) 1896 arXiv:1111.6097 hep-ph.
3 M. Cacciari and G. P. Salam, Phys. Lett. B 641 (2006) 57 hep-ph/0512210.
4 M. Cacciari, G. P. Salam and G. Soyez, JHEP 0804 (2008) 063 arXiv:0802.1189 hep-ph.
5 A. L. Read, J. Phys. G 28 (2002) 2693.
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.
Neutrinos and collider physics Deppisch, Frank F; Bhupal Dev, P S; Pilaftsis, Apostolos
New journal of physics,
08/2015, Letnik:
17, Številka:
7
Journal Article
Recenzirano
Odprti dostop
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.
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.
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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