Higgs Potential Parameters Research Articles

Connecting the Higgs potential and primordial black holes

It was recently demonstrated that small small black holes can act as seeds for nucleating decay of the metastable Higgs vacuum, dramatically increasing the tunneling probability. Any primordial black hole lighter than $4.5 \times 10^{14}$g at formation would have evaporated by now, and in the absence of new physics beyond the standard model, would therefore have entered the mass range in which seeded decay occurs, however, such true vacuum bubbles must percolate in order to completely destroy the false vacuum; this depends on the bubble number density and the rate of expansion of the universe. Here, we compute the fraction of the universe that has decayed to the true vacuum as a function of the formation temperature (or equivalently, mass) of the primordial black holes, and the spectral index of the fluctuations responsible for their formation. This allows us to constrain the mass spectrum of primordial black holes given a particular Higgs potential and conversely, should we discover primordial black holes of definite mass, we can constrain the Higgs potential parameters.

Baryon Asymmetry from a Composite Higgs Boson

We study the nature of the electroweak phase transition (EWPT) in models where the Higgs boson emerges as a pseudo-Nambu-Goldstone boson of an approximate global symmetry of a new strongly interacting sector confining around the TeV scale. Our analysis focuses for the first time on the case where the EWPT is accompanied by the confinement phase transition of the strong sector. We describe the confinement in terms of the dilaton, the pseudo-Nambu-Goldstone boson of spontaneously broken conformal invariance of the strong sector. The dilaton can either be a mesonlike or a glueball-like state and we demonstrate a significant qualitative difference in their dynamics. We show that the EWPT can naturally be strongly first order, due to the nearly conformal nature of the dilaton potential. Furthermore, we examine the sizable scale variation of the Higgs potential parameters during the EWPT. In particular, we consider in detail the case of a varying top quark Yukawa coupling, and show that the resulting CP violation is sufficient for successful electroweak baryogenesis. We demonstrate that this source of CP violation is compatible with existing flavor and CP constraints. Our scenario can be tested in complementary ways: by measuring the CP-odd top Yukawa coupling in electron electric dipole moment experiments, by searching for dilaton production and deviations in Higgs couplings at colliders, and through gravitational waves at LISA.

Exploring extended scalar sectors with di-Higgs signals: a Higgs EFT perspective

We consider extended scalar sectors of the Standard Model as ultraviolet complete motivations for studying the effective Higgs self-interaction operators of the Standard Model effective field theory. We investigate all motivated heavy scalar models which generate the dimension-six effective operator, |H|6, at tree level and proceed to identify the full set of tree-level dimension-six operators by integrating out the heavy scalars. Of seven models which generate |H|6 at tree level only two, quadruplets of hypercharge Y = 3YH and Y = YH, generate only this operator. Next we perform global fits to constrain relevant Wilson coefficients from the LHC single Higgs measurements as well as the electroweak oblique parameters S and T. We find that the T parameter puts very strong constraints on the Wilson coefficient of the |H|6 operator in the triplet and quadruplet models, while the singlet and doublet models could still have Higgs self-couplings which deviate significantly from the standard model prediction. To determine the extent to which the |H|6 operator could be constrained, we study the di-Higgs signatures at the future 100 TeV collider and explore future sensitivity of this operator. Projected onto the Higgs potential parameters of the extended scalar sectors, with 30 ab−1 luminosity data we will be able to explore the Higgs potential parameters in all seven models.

Critical temperatures in extensions of Higgs sector

In this paper the control parameters of the Higgs potential are considered in the framework of supersymmetric models MSSM and Next-to-MSSM. The determination of these parameters is an important part related to the explanation of the CP violation evidence and electroweak phase transition evolution from the energy of the supersymmetry scale to the standard model energy scale. There is a discussion here on the problem of violation of CP invariance and its effect on the Higgs potential control parameters determination and the dark matter experimental constraints. Also the problem of determining the Potential ↔ Free Energy parameters from the points of temperature field theory and critical temperatures view is considered.

Theoretical constraints on masses of heavy particles in Left-Right symmetric models

Left-Right symmetric models with general $g_L \neq g_R$ gauge couplings which include bidoublet and triplet scalar multiplets are studied. Possible scalar mass spectra are outlined by imposing Tree-Unitarity, and Vacuum Stability criteria and also using the bounds on neutral scalar masses $M_{\rm H^{ FCNC}}$ which assure the absence of Flavour Changing Neutral Currents (FCNC). We are focusing on mass spectra relevant for the LHC analysis, i.e., the scalar masses are around TeV scale. As all non-standard heavy particle masses are related to the vacuum expectation value (VEV) of the right-handed triplet ($v_R$), the combined effects of relevant Higgs potential parameters and $M_{\rm H^{ FCNC}}$ regulate the lower limits of heavy gauge boson masses. The complete set of Renormalization Group Evolutions for all couplings are provided at the 1-loop level, including the mixing effects in the Yukawa sector. Most of the scalar couplings suffer from the Landau poles at the intermediate scale $Q \sim 10^{6.5}$ GeV, which in general coincides with violation of the Tree-Unitarity bounds.

Finite-Temperature Higgs Potentials

In the present article we consider the short description of the “Finite-Temperature Higgs Potentials” program for calculating loop integrals at vanishing external momenta and applications for extended Higgs potentials reconstructions. Here we collect the analytic forms of the relevant loop integrals for our work in reconstruction of the effective Higgs potential parameters in extended models (MSSM, NMSSM and etc.).

Degenerate Higgs bosons decays toγγandZγin the type II seesaw model

Using the most recent results of CMS and ATLAS, we study the Higgs decays to $\ensuremath{\gamma}\ensuremath{\gamma}$ and $Z\ensuremath{\gamma}$ in the scenario where the two $CP$-even Higgs predicted by the type II seesaw model (Higgs triplet models) are close to mass degenerate with a mass near 125 GeV. We analyze the effects of the Higgs potential parameters constrained by the full set of perturbative unitarity, boundedness from below as well as from precision electroweak measurements on these decay modes. Our analysis demonstrates that the observed excess in the diphoton Higgs decay channel can be interpreted in our scenario within a delineated region controlled by ${\ensuremath{\lambda}}_{1}$ and ${\ensuremath{\lambda}}_{4}$ coupling. We also find a deviation in the Higgs decay to $Z\ensuremath{\gamma}$ with respect to the Standard Model prediction and the largest enhancement is found for a ratio ${R}_{Z\ensuremath{\gamma}}$ of the order 1.6. Furthermore we show that consistency with current ATLAS data on the diphoton decay channel favors a light doubly charged Higgs with mass in the range 92--180 GeV. Finally, we find that the $\ensuremath{\gamma}\ensuremath{\gamma}$ and $Z\ensuremath{\gamma}$ Higgs decay modes are generally correlated and the magnitude of correlation is sensitive to the sign of the ${\ensuremath{\lambda}}_{1}$ parameter.

Computation of neutrino masses in R-parity violating supersymmetry: SOFTSUSY3.2

The program SOFTSUSY can calculate tree-level neutrino masses in the R-parity violating minimal supersymmetric standard model (MSSM) with real couplings. At tree-level, only one neutrino acquires a mass, in contradiction with neutrino oscillation data. Here, we describe an extension to the SOFTSUSY program which includes one-loop R-parity violating effectsʼ contributions to neutrino masses and mixing. Including the one-loop effects refines the radiative electroweak symmetry breaking calculation, and may result in up to three massive, mixed neutrinos. This paper serves as a manual to the neutrino mass prediction mode of the program, detailing the approximations and conventions used. Program summary Program title: SOFTSUSY Catalogue identifier: ADPM_v3_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ADPM_v3_0.html Program obtainable from: CPC Program Library, Queenʼs University, Belfast, N. Ireland Licensing provisions: GNU General Public License version 3 No. of lines in distributed program, including test data, etc.: 93 291 No. of bytes in distributed program, including test data, etc.: 1 288 618 Distribution format: tar.gz Programming language: C++, Fortran Computer: Personal computer Operating system: Tested on Linux 4.x Word size: 32 bits Classification: 11.1, 11.6 Catalogue identifier of previous version: ADPM_v2_0 Journal reference of previous version: Comput. Phys. Comm. 181 (2010) 232 Does the new version supersede the previous version?: Yes Nature of problem: Calculation of neutrino masses and the neutrino mixing matrix at one-loop level in the R-parity violating minimal supersymmetric standard model. The solution to the renormalisation group equations must be consistent with a high or weak-scale boundary condition on supersymmetry breaking parameters and R-parity violating parameters, as well as a weak-scale boundary condition on gauge couplings, Yukawa couplings and the Higgs potential parameters. Solution method: Nested iterative algorithm. Reasons for new version: Added functionality (computation of all three neutrino masses and their mixings) and bug-fixes. Summary of revisions: • Additional error flags for which particle has become tachyonic. • Allowing tanb(MX) boundary condition. New SOFTSUSY Block 7 allows the user to change the number of loops in calculating Higgs mass and electroweak symmetry breaking calculation to be 1 or 2. • mGMSB fine tuning fixed: thanks to Matthias Hamer for pointing out the bug. • RPV SUSY couplings now able to be set at MZ as well as at SUSY breaking scale. • Default output format from softpoint.x is SLHA. • Fixed third-family mixing contribution to gluino mass. MIXING = − 1 now banned. • Small bug-fix in charged Higgs loop calculation, in gaugino contribution. Now respects Z2 (U1R-PQ) flip exactly due to bug-fixes in gluino mass. • Gravitino default mass changed to Planck scale. • Added one-loop RPV loop corrections to neutrino masses allows computation of neutrino oscillation parameters. Restrictions: SOFTSUSY will provide a solution only in the perturbative régime and it assumes that all couplings of the MSSM are real (i.e. CP-conserving). Running time: A second per parameter point.

HidSecSOFTSUSY: Incorporating effects from hidden sectors in the numerical computation of the MSSM spectrum

SOFTSUSY is a software designed to solve the RG equations of the MSSM and compute its low energy spectrum. HidSecSOFTSUSY is an extension of the SOFTSUSY package which modifies the beta functions to include contributions from light dynamic fields in the hidden sector. Program summary Program title: HidSecSOFTSUSY Catalogue identifier: AEHP_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEHP_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 4167 No. of bytes in distributed program, including test data, etc.: 141 411 Distribution format: tar.gz Programming language: C++, Fortran Computer: Personal computer Operating system: Tested on GNU/Linux Word size: 32 bits Classification: 11.6 External routines: Requires an installed version of SOFTSUSY ( http://projects.hepforge.org/softsusy/) Nature of problem: Calculating supersymmetric particle spectrum and mixing parameters while incorporating dynamic modes from the hidden sector into the renormalization group equations. The solution to the equations must be consistent with a high-scale boundary condition on supersymmetry breaking parameters, as well as a weak-scale boundary condition on gauge couplings, Yukawa couplings and the Higgs potential parameters. Solution method: Nested iterative algorithm. Running time: A few seconds per parameter point.

Including R-parity violation in the numerical computation of the spectrum of the minimal supersymmetric standard model: SOFTSUSY3.0

Current publicly available computer programs calculate the spectrum and couplings of the minimal supersymmetric standard model under the assumption of R-parity conservation. Here, we describe an extension to the SOFTSUSY program which includes R-parity violating effects. The user provides a theoretical boundary condition upon the high-scale supersymmetry breaking R-parity violating couplings. Successful radiative electroweak symmetry breaking, electroweak and CKM matrix data are used as weak-scale boundary conditions. The renormalisation group equations are solved numerically between the weak scale and a high energy scale using a nested iterative algorithm. This paper serves as a manual to the R-parity violating mode of the program, detailing the approximations and conventions used. Program summary Program title: SOFTSUSY v3.0 Catalogue identifier: ADPM_v2_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ADPM_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 75 927 No. of bytes in distributed program, including test data, etc.: 570 916 Distribution format: tar.gz Programming language: C++, Fortran Computer: Personal computer Operating system: Tested on Linux 4.x Word size: 32 bits Classification: 11.6 Catalogue identifier of previous version: ADPM_v1_0 Journal reference of previous version: Comput. Phys. Comm. 143 (2002) 305 Does the new version supersede the previous version?: Yes Nature of problem: Calculating supersymmetric particle spectrum and mixing parameters in the R-parity violating minimal supersymmetric standard model. The solution to the renormalisation group equations must be consistent with a high-scale boundary condition on supersymmetry breaking parameters and R p parameters, as well as a weak-scale boundary condition on gauge couplings, Yukawa couplings and the Higgs potential parameters. Solution method: Nested iterative algorithm Reasons for new version: This is an extension to the SOFTSUSY program which includes R-parity violating effects. The user provides a theoretical boundary condition upon the high-scale supersymmetry breaking R-parity violating couplings. Successful radiative electroweak symmetry breaking, electroweak and CKM matrix data are used as weak-scale boundary conditions. The renormalisation group equations are solved numerically between the weak scale and a high energy scale using a nested iterative algorithm. The paper serves as a manual to the R-parity violating mode of the program, detailing the approximations and conventions used. Restrictions: SOFTSUSY3.0 will provide a solution only in the perturbative regime and it assumes that all couplings of the MSSM are real (i.e. CP-conserving). The iterative SOFTSUSY algorithm will not converge if parameters are too close to a boundary of successful electroweak symmetry breaking, but a warning flag will alert the user to this fact. Running time: A few seconds per parameter point.

Panglossian prospects for detecting neutralino dark matter in light of natural priors?

In most global fits of the constrained minimal supersymmetric model (CMSSM) to indirect data, the a priori likelihoods of any two points in tan β are treated as equal, and the more fundamental μ and B Higgs potential parameters are fixed by potential minimization conditions. We find that, if instead a flat (``natural'') prior measure on μ and B is placed, a strong preference exists for the focus point region from fits to particle physics and cosmological data. In particular, we find that the lightest neutralino is strongly favored to be a mixed bino-higgsino ( ~ 10% higgsino). Such mixed neutralinos have large elastic scattering cross sections with nuclei, leading to extremely promising prospects for both underground direct detection experiments and neutrino telescopes. In particular, the majority of the posterior probability distribution falls within parameter space within an order of magnitude of current direct detection constraints. Furthermore, neutralino annihilations in the sun are predicted to generate thousands of neutrino induced muon events per years at IceCube. Thus, assuming the framework of the CMSSM and using the natural prior measure, modulo caveats regarding astrophysical uncertainties, we are likely to be living in a world with good prospects for the direct and indirect detection of neutralino dark matter. These conclusions have a dependence upon the prior measure, which more data will reduce.

Conditions forCPviolation in the general two-Higgs-doublet model

The most general Higgs potential of the two-Higgs-doublet model (2HDM) contains three squared-mass parameters and seven quartic self-coupling parameters. Among these, one squared-mass parameter and three quartic coupling parameters are potentially complex. The Higgs potential explicitly violates $CP$ symmetry if and only if no choice of basis exists in the two-dimensional Higgs flavor space in which all the Higgs potential parameters are real. We exhibit four independent potentially complex invariant (basis-independent) combinations of mass and coupling parameters and show that the reality of all four invariants provides the necessary and sufficient conditions for an explicitly $CP$-conserving 2HDM scalar potential. Additional potentially complex invariants can be constructed that depend on the Higgs field vacuum expectation values (vevs). We demonstrate how these can be used together with the vev-independent invariants to distinguish between explicit and spontaneous $CP$ violation in the Higgs sector.

Two-Higgs-doublet model from the group-theoretic perspective

In the two-Higgs-doublet model, different Higgs doublets can be viewed as components of a generic “hyperspinor”. We decompose the Higgs potential of this model into irreducible representations of the SU(2) group of transformations of this hyperspinor. We discuss invariant combinations of Higgs potential parameters λi that arise in this decomposition and provide simple and concise sets of conditions for the hidden Z2-symmetry, Peccei–Quinn symmetry, and explicit CP-conservation in 2HDM. We show that some results obtained previously by brute-force calculations are reduced to simple linear algebraic statements in our approach.

Finite supersymmetric grand unified theory reexamined

We analyze the finite supersymmetric SU(5) grand unified model taking into account the threshold corrections at the grand unified theory and supersymmetry breaking scales and the problem of electroweak symmetry breaking which is particularly important in the case of large $\mathrm{tan}\ensuremath{\beta}.$ We find that there are still parameter regions where the low-energy experimental values are consistently reproduced and the Higgs potential parameters actually satisfy both constraints for large $\mathrm{tan}\ensuremath{\beta}$ and radiative electroweak symmetry breaking, provided that a new free parameter is introduced in the boundary condition of the Higgs soft-mass parameter, while it preserves the finiteness requirements.

Spontaneous CP violation in an SU(3) L⊗U(1) Y electroweak model

We study the possibility of finding spontaneous CP violation within an SU(3) L ⊗U(1) Y> electroweak model. We show that the mechanism is allowed for a certain range of the Higgs potential parameters only when a scalar sextuplet is included to provide the lepton masses.

Maximal CP violation in the Higgs sector and its effect on the ρ parameter

We study the conditions of maximal CP violation in the neutral Higgs mass matrix of the two Higgs doublet model. We get fixed values of tan β and constraints on the Higgs potential parameters. Two neutral Higgs scalars are constrained to be lighter than the charged Higgs scalar and these two Higgs scalars are expected to be almost degenerate due to the smallness of the h parameter, where h is the CP violating coupling constant of the Higgs interaction. The radiative correction of the ρ parameter from the Higgs scalar exchange is rather small and its sign negative for a wide range of Higgs masses. It follows that maximum CP violation in the two Higgs doublet model is safely allowed for the ρ parameter without the custodial symmetry.