In the context of left-right symmetry, we revisit the Keung-Senjanović production of right-handed WR bosons and heavy neutrinos N at high energy colliders. We develop a multibinned sensitivity ...measure and use it to estimate the sensitivity for the entire range of N masses, spanning the standard and merged prompt signals, displaced vertices and the invisible N region. The estimated sensitivity of the LHC with 300/fb integrated luminosity ranges from 5 to beyond 7 TeV, while the future 33(100) TeV collider’s reach with 3/ab extends to 12(26) TeV.
We are launching FindBounce, a Mathematica package for the evaluation of the Euclidean bounce action that enters the decay rate of metastable states in quantum and thermal field theories. It is based ...on the idea of polygonal bounces, which is a semi-analytical approach to solving the bounce equation by discretizing the potential into piecewise linear segments. This allows for a fast and robust evaluation of arbitrary potentials with specified precision and any number of scalar fields. Time cost grows linearly with the number of fields and/or the number of segments. Computation with 20 fields takes ∼2 s with 0.5% accuracy of the action. The FindBounce function is simple to use with the native Mathematica look and feel, it is easy to install, and comes with detailed documentation and physical examples, such as the calculation of the nucleation temperature. We also provide timing benchmarks with comparisons to existing tools, where applicable.
Program title:FindBounce
CPC Library link to program files:http://dx.doi.org/10.17632/tysw84skx3.1
Developer’s repository link:https://github.com/vguada/FindBounce
Licensing provisions: GNU General Public License 3
Programming language:Mathematica
Nature of problem: Evaluation of the Euclidean bounce action that controls the decay rate of metastable local minima in thermal and quantum field theories.
Solution method: Semi-analytical solution of a system of coupled differential equations, based on the polygonal bounce idea (Guada et al., 2019).
Restrictions:Mathematica version 10 or above, works in D=3,4.
Majorana Higgses at colliders Nemevšek, Miha; Nesti, Fabrizio; Vasquez, Juan Carlos
The journal of high energy physics,
04/2017, Volume:
2017, Issue:
4
Journal Article
Peer reviewed
Open access
A
bstract
Collider signals of heavy Majorana neutrino mass origin are studied in the minimal Left-Right symmetric model, where their mass is generated spontaneously together with the breaking of ...lepton number. The right-handed triplet Higgs boson Δ, responsible for such breaking, can be copiously produced at the LHC through the Higgs portal in the gluon fusion and less so in gauge mediated channels. At Δ masses below the opening of the
V V
decay channel, the two observable modes are pair-production of heavy neutrinos via the triplet gluon fusion
gg
→ Δ →
NN
and pair production of triplets from the Higgs
h
→ ΔΔ → 4
N
decay. The latter features tri- and quad same-sign lepton final states that break lepton number by four units and have no significant background. In both cases up to four displaced vertices may be present and their displacement may serve as a discriminating variable. The backgrounds at the LHC, including the jet fake rate, are estimated and the resulting sensitivity to the Left-Right breaking scale extends well beyond 10 TeV. In addition, sub-dominant radiative modes are surveyed: the
γγ
,
Zγ
and lepton flavour violating ones. Finally, prospects for Δ signals at future
e
+
e
−
colliders are presented.
We show that within the left-right symmetric model, lepton number violating decays of the Higgs boson can be discovered at the LHC. The process is due to the mixing of the Higgs boson with the ...triplet that breaks parity. As a result, the Higgs boson can act as a gateway to the origin of the heavy Majorana neutrino mass. To assess the LHC reach, a detailed collider study of the same-sign dileptons plus jets channel is provided. This process is complementary to the existing nuclear and collider searches for lepton number violation and can probe the scale of parity restoration even beyond other direct searches.
In the minimal left-right model the choice of left-right symmetry is twofold: either generalized parity P or charge conjugation C. In the minimal model with spontaneously broken strict P, a large ...tree-level contribution to strong CP violation can be computed in terms of the spontaneous phase alpha . Searches for the neutron electric dipole moments then constrain the size of alpha . Following the latest update on indirect CP violation in the kaon sector, a bound on WR mass at 20 TeV is set. Possible ways out of this bound require a further hypothesis, either a relaxation mechanism or explicit breaking of P. To this end, the chiral loop of the neutron electric dipole moment at next-to-leading order is recomputed and provides an estimate of the weak contribution. Combining this constraint with other CP-violating observables in the kaon sector allows for MWR > ~ 3 TeV. On the other hand, C symmetry is free from such constraints, leaving the right-handed scale within the experimental reach.
Entropy production is a necessary ingredient for addressing the overpopulation of thermal relics. It is widely employed in particle physics models for explaining the origin of dark matter. A ...long-lived particle that decays to the known particles, while dominating the universe, plays the role of the dilutor. We point out the impact of its partial decay to dark matter on the primordial matter power spectrum. For the first time, we derive a stringent limit on the branching ratio of the dilutor to dark matter from large scale structure observation using the sloan digital sky survey data. This offers a novel tool for testing models with a dark matter dilution mechanism. We apply it to the left-right symmetric model and show that it firmly excludes a large portion of parameter space for right-handed neutrino warm dark matter.
We present a systematic comparison of doubly charged Higgs boson production mechanisms at hadron colliders in the context of the type II seesaw model, emphasizing the importance of higher-order ...corrections and subdominant channels. We consider the Drell-Yan channel at next-to-leading order in QCD, photon fusion at leading order, gluon fusion with resummation of threshold logarithms up to next-to-next-to-next-to-leading logarithmic accuracy, and same-sign weak boson fusion at next-to-leading order in QCD. For the Drell-Yan process, we study the impact of a static jet veto at next-to-leading order matched to the resummation of jet veto scale logarithms at next-to-next-to-leading logarithmic accuracy. For the photon fusion channel, the dependence on modeling photon parton distribution functions is definitively assessed. To model vector boson fusion at next-to-leading order, we include all interfering topologies at O(α4) and propose a method for introducing generator-level cuts within the MC@NLO formalism. Our results are obtained using a Monte Carlo tool chain linking the feynrules, nloct and madgraph5_amc@nlo programs and have necessitated the development of new, publicly available, Universal feynrules Output libraries that encode the interactions between the type II seesaw scalars and Standard Model particles. Libraries are compatible with both the normal and inverted ordering of Majorana neutrino masses.
We discuss an exact false vacuum decay rate at one loop for a real and complex scalar field in a quartic-quartic potential with two tree-level minima. The bounce solution is used to compute the ...functional determinant from both fluctuations. We obtain the finite product of eigenvalues and remove translational zero modes. The orbital modes are regularized with the zeta function and we end up with a complete renormalized decay rate. We derive simple expansions in the thin and thick wall limits and determine their validity.
The scalar sector of the minimal left-right model at TeV scale is revisited in light of the large quartic coupling needed for a heavy flavor-changing scalar. The stability and perturbativity of the ...effective potential is discussed and merged with constraints from low-energy processes. Thus, the perturbative level of the left-right scale is sharpened. Lower limits on the triplet scalars are also derived: The left-handed triplet is bounded by oblique parameters, while the doubly charged right-handed component is limited by the harrowrightgammagamma, Zgamma decays. Current constraints disfavor their detection as long as W sub()Ris within the reach of the LHC.
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