arXiv subjects

Jae-hyeon Park

Publications and source records attributed to Jae-hyeon Park.

At least 19 recordsLinked to original sources

arXiv2023

Supernova Axion Emissivity with $Δ(1232)$ Resonance in Heavy Baryon Chiral Perturbation Theory

In this paper, we evaluate the energy loss rate of supernovae induced by the axion emission process $π^- + p \to n + a$ with the $Δ(1232)$ resonance in the heavy baryon chiral perturbation theory for the first time. Given the axion-nucleon-$Δ$ interactions, we include the previously ignored $Δ$-mediated graphs to the $π^- + p \to n + a$ process. In particular, the $Δ^0$-mediated diagram can give a resonance contribution to the supernova axion emission rate when the center-of-mass energy of the pion and proton approaches the $Δ(1232)$ mass. With these new contributions, we find that for the typical supernova temperatures, compared with the earlier work with the axion-nucleon (and axion-pion-nucleon contact) interactions, the supernova axion emissivity can be enhanced by a factor of $\sim$4(2) in the Kim-Shifman-Vainshtein-Zakharov model and up to a factor of $\sim$5(2) in the Dine-Fischler-Srednicki-Zhitnitsky model with small $\tanβ$ values. Remarkably, we notice that the $Δ(1232)$ resonance gives a destructive contribution to the supernova axion emission rate at high supernova temperatures, which is a nontrivial result in this study.

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arXiv2022

Phenomenological constraints on light mixed sneutrino dark matter scenarios

In supersymmetric models with Dirac neutrinos, the lightest sneutrino can be an excellent thermal dark matter candidate when the soft sneutrino trilinear parameter is large. We focus on scenarios where the mass of the mixed sneutrino is of the order of GeV and sensitivity of dark matter direct detection is weak. We investigate phenomenological constraints on the model parameter space including the vacuum stability bound. We show that the allowed regions can be explored by measuring Higgs boson properties at future collider experiments.

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arXiv2021

Leveraging Quantum Annealer to identify an Event-topology at High Energy Colliders

With increasing energy and luminosity available at the Large Hadron collider (LHC), we get a chance to take a pure bottom-up approach solely based on data. This will extend the scope of our understanding about Nature without relying on theoretical prejudices. The required computing resource, however, will increase exponentially with data size and complexities of events if one uses algorithms based on a classical computer. In this letter we propose a simple and well motivated method with a quantum annealer to identify an event-topology, a diagram to describe the history of particles produced at the LHC. We show that a computing complexity can be reduced significantly to the order of polynomials which enables us to decode the "Big" data in a very clear and efficient way. Our method achieves significant improvements in finding a true event-topology, more than by a factor of two compared to a conventional method.

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arXiv2019

Higgs potential near-criticality from a de Sitter swampland-like condition

Motivated by the recently proposed de Sitter swampland conjecture, a formally same condition imposed instead on the convex and real exact effective potential is contemplated. Compared to the original conjecture, the modified condition admits a broader class of low-energy effective theories such as those with local maxima and/or false de Sitter vacua with some restrictions, as long as there is an anti-de Sitter vacuum. The observed accelerating expansion of the universe might therefore be attributed to a quintessence or a metastable vacuum. The former solution can be simplified and thus better compatible with phenomenological constraints thanks to the convexity of the effective potential. Among the latter class of solutions is found the enthralling possibility that the modified condition is in fact behind the experimentally favoured metastability of the Higgs potential with an instability scale below or around the Planck scale.

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arXiv2018

FlexibleSUSY: Precise automated calculations in any BSM theory

FlexibleSUSY is a software package for various calculations in any model of physics beyond the standard model (not just any supersymmetric model). FlexibleSUSY can solve boundary value problems and uses this to find $\overline{DR}/\overline{MS}$ parameters and calculate the Higgs and BSM particle masses, as well as other observables. FlexibleSUSY is designed to be adaptable, fast, precise and reliable. We describe FlexibleSUSY with particular emphasis on recent developments and the state of the art Higgs mass calculations it can perform. We also show some applications to illustrate how it can be used to obtain interesting physics results with the highest precision possible and with remarkable speed.

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arXiv2018

Higgs mass and vacuum stability with high-scale supersymmetry

In the high-scale (split) MSSM, the measured Higgs mass sets an upper bound on the supersymmetric scalar mass scale MSUSY around $10^{11}$ ($10^{8}$) GeV, for $\tanβ$ in the standard range and the central value of the top quark mass $m_t$. This article discusses how maximal MSUSY is affected by negative threshold corrections to the quartic Higgs coupling arising from the sbottom and stop trilinear couplings. In the high-scale MSSM with very high $\tanβ$, the electroweak vacuum decay due to the large bottom Yukawa coupling rules out the possibility of raising MSUSY beyond the above limit. In cases with large $A_b$ or $A_t$, MSUSY as a common mass of the extra fermions and scalars can be as high as $10^{17}$ GeV remaining consistent with $m_h$ and the vacuum longevity if $m_t$ is smaller than the central value by $2σ$. For the central value of $m_t$, the upper limit on MSUSY does not change very much owing to the metastability, which is the case also in the split MSSM even with $\pm 2σ$ variations in $m_t$.

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arXiv2018

FlexibleSUSY 2.0: Extensions to investigate the phenomenology of SUSY and non-SUSY models

We document major new features and improvements of FlexibleSUSY, a Mathematica and C++ package with a dependency on the external package SARAH, that generates fast and precise spectrum generators. The extensions presented here significantly increase the generality and capabilities of the FlexibleSUSY package, which already works with a wide class of models, while maintaining an elegant structure and easy to use interfaces. The FlexibleBSM extension makes it possible to also create spectrum generators for non-supersymmetric extensions of the Standard Model. The FlexibleCPV extension adds the option of complex parameters to the spectrum generators, allowing the study of many interesting models with new sources of $CP$ violation. FlexibleMW computes the decay of the muon for the generated model and thereby allows FlexibleSUSY to predict the mass of the $W$ boson from the input parameters by using the more precise electroweak input of $\{ G_F, M_Z, α_{\text{em}} \}$ instead of $\{ M_W, M_Z, α_{\text{em}} \}$. The FlexibleAMU extension provides a calculator of the anomalous magnetic moment of the muon in any model FlexibleSUSY can generate a spectrum for. FlexibleSAS introduces a new solver for the boundary value problem which makes use of semi-analytic expressions for dimensionful parameters to find solutions in models where the classic two-scale solver will not work such as the constrained E$_6$SSM. FlexibleEFTHiggs is a hybrid calculation of the Higgs mass which combines the virtues of both effective field theory calculations and fixed-order calculations. All of these extensions are included in FlexibleSUSY 2.0, which is released simultaneously with this manual.

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arXiv2017

Precise Higgs mass calculations in (non-)minimal supersymmetry at both high and low scales

We present FlexibleEFTHiggs, a method for calculating the SM-like Higgs pole mass in SUSY (and even non-SUSY) models, which combines an effective field theory approach with a diagrammatic calculation. It thus achieves an all order resummation of leading logarithms together with the inclusion of all non-logarithmic 1-loop contributions. We implement this method into FlexibleSUSY and study its properties in the MSSM, NMSSM, E6SSM and MRSSM. In the MSSM, it correctly interpolates between the known results of effective field theory calculations in the literature for a high SUSY scale and fixed-order calculations in the full theory for a sub-TeV SUSY scale. We compare our MSSM results to those from public codes and identify the origin of the most significant deviations between the DR-bar programs. We then perform a similar comparison in the remaining three non-minimal models. For all four models we estimate the theoretical uncertainty of FlexibleEFTHiggs and the fixed-order DR-bar programs thereby finding that the former becomes more precise than the latter for a SUSY scale above a few TeV. Even for sub-TeV SUSY scales, FlexibleEFTHiggs maintains the uncertainty estimate around 2-3 GeV, remaining a competitive alternative to existing fixed-order computations.

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arXiv2016

LHC 750 GeV diphoton excess and muon $(g-2)$

We consider implications of the diphoton excess recently observed at the LHC on the anomalous magnetic dipole moment of the muon $(g-2)_μ= 2 a_μ$, hypothesizing that the possible 750 GeV resonance is a (pseudo)scalar particle. The (pseudo)scalar-$γ$-$γ$ interaction implied by the diphoton events might generically contribute to $a_μ$ via 2-loop Barr-Zee type diagrams in a broad class of models. If the scalar is an $SU(2)_L$ singlet, the new contribution to $a_μ$ is much smaller than the current anomaly, $Δa_μ\equiv a_μ^{\rm exp}-a_μ^{\rm SM} \approx (30 \pm 10) \times 10^{-10}$, since the scalar can complete the Barr-Zee diagrams only through its mixing with the Standard Model Higgs boson. If the (pseudo)scalar belongs to an $SU(2)_L$ doublet in an extended Higgs sector, then by contrast, $Δa_μ$ can be easily accommodated with the aid of an enhanced Yukawa coupling of the (pseudo)scalar to the muon such as in the Type-II or -X two Higgs doublet model.

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arXiv2015

GM2Calc: Precise MSSM prediction for $(g - 2)$ of the muon

We present GM2Calc, a public C++ program for the calculation of MSSM contributions to the anomalous magnetic moment of the muon, $(g-2)_μ$. The code computes $(g-2)_μ$ precisely, by taking into account the latest two-loop corrections and by performing the calculation in a physical on-shell renormalization scheme. In particular the program includes a $\tanβ$ resummation so that it is valid for arbitrarily high values of $\tanβ$, as well as fermion/sfermion-loop corrections which lead to non-decoupling effects from heavy squarks. GM2Calc can be run with a standard SLHA input file, internally converting the input into on-shell parameters. Alternatively, input parameters may be specified directly in this on-shell scheme. In both cases the input file allows one to switch on/off individual contributions to study their relative impact. This paper also provides typical usage examples not only in conjunction with spectrum generators and plotting programs but also as C++ subroutines linked to other programs.

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arXiv2015

Large muon $(g-2)$ from TeV-scale MSSM with infinite $\tanβ$

The muon anomalous magnetic moment $a_μ$ is studied in the infinite $\tanβ$ limit of the MSSM. Since the muon mass arises completely from loop effects, large corrections to $a_μ$ are expected in comparison to the usual case with moderately high $\tanβ$. Due to the qualitatively different parameter dependence, the gap between the experimental value and the Standard Model prediction can be filled only in parameter volumes in which a mass hierarchy suppresses the chargino loop in favour of the neutralino contribution. Two such possibilities are found to have either large Higgsino mass or large muon sneutrino mass. Supersymmetric particles even at the TeV scale can lead to the best fit of $a_μ$.

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arXiv2015

Large muon $(g-2)$ with TeV-scale SUSY masses for $\tanβ\to\infty$

The muon anomalous magnetic moment $a_μ$ is investigated in the MSSM for $\tanβ\to\infty$. This is an attractive example of radiative muon mass generation with completely different qualitative parameter dependence compared to the MSSM with the usual, finite $\tanβ$. The observed, positive difference between the experimental and Standard Model value can only be explained if there are mass splittings, such that bino contributions dominate over wino ones. The two most promising cases are characterized either by large Higgsino mass $μ$ or by large left-handed smuon mass $m_L$. The required mass splittings and the resulting $a_μ^\text{SUSY}$ are studied in detail. It is shown that the current discrepancy in $a_μ$ can be explained even in cases where all SUSY masses are at the TeV scale. The paper also presents useful analytical formulas, approximations for limiting cases, and benchmark points.

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arXiv2015

FlexibleSUSY -- A spectrum generator generator for supersymmetric models

We introduce FlexibleSUSY, a Mathematica and C++ package, which generates a fast, precise C++ spectrum generator for any SUSY model specified by the user. The generated code is designed with both speed and modularity in mind, making it easy to adapt and extend with new features. The model is specified by supplying the superpotential, gauge structure and particle content in a SARAH model file; specific boundary conditions e.g. at the GUT, weak or intermediate scales are defined in a separate FlexibleSUSY model file. From these model files, FlexibleSUSY generates C++ code for self-energies, tadpole corrections, renormalization group equations (RGEs) and electroweak symmetry breaking (EWSB) conditions and combines them with numerical routines for solving the RGEs and EWSB conditions simultaneously. The resulting spectrum generator is then able to solve for the spectrum of the model, including loop-corrected pole masses, consistent with user specified boundary conditions. The modular structure of the generated code allows for individual components to be replaced with an alternative if available. FlexibleSUSY has been carefully designed to grow as alternative solvers and calculators are added. Predefined models include the MSSM, NMSSM, E$_6$SSM, USSM, R-symmetric models and models with right-handed neutrinos.

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arXiv2014

FlexibleSUSY - a meta spectrum generator for supersymmetric models

FlexibleSUSY is a software package that takes as input descriptions of (non-)minimal supersymmetric models written in Wolfram/Mathematica and generates a set of spectrum generator libraries and executables, with the aid of SARAH. The design goals are precision, reliability, modularity, speed, and readability of the code. The boundary conditions are independent C++ objects that are plugged into the boundary value problem solver together with the model objects. This clean separation makes it easy to adapt the generated code for individual projects. The current status of the interface and implementation is sketched.

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arXiv2014

Understanding the correlation between $(g-2)_μ$ and $μ\rightarrow e γ$ in the MSSM

The supersymmetric contributions to the muon anomalous magnetic moment $a_μ$ and to the decay $μ\to eγ$ are given by very similar Feynman diagrams. Previous works reported correlations in specific scenarios, in particular if $a_μ$ is dominated by a single diagram. In this work we give an extensive survey of the possible correlations. We discuss examples of single-diagram domination with particularly strong correlations, and provide corresponding benchmark parameter points. We show how the correlations are weakened by significant cancellations between diagrams in large parts of the MSSM parameter space. Nevertheless, the order of magnitude of $\text{BR}(μ\to e γ)$ for a fixed flavor-violating parameter can often be predicted. We summarize the behavior by plotting the correlations as well as resulting bounds on the flavor-violating parameters under various assumptions on the MSSM spectrum.

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arXiv2014

Lepton flavour violation from right-handed neutrino thresholds

Charged lepton flavour violation is reappraised in the context of supersymmetric see-saw mechanism. It is pointed out that a non-trivial flavour structure of right-handed neutrinos, whose effect has been thus far less studied, can give rise to significant slepton flavour transitions. Under the premise that the neutrino Yukawa couplings are of O(1), the right-handed neutrino mixing contribution could form a basis of the $μ\rightarrow e γ$ amplitude which by itself might lead to an experimentally accessible rate, given a typical low-energy sparticle spectrum. Emphasis is placed on the crucial role of the recently measured lepton mixing angle $θ_{13}$ as well as the leptonic CP-violating phases.

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arXiv2014

LHC explores what LEP hinted at: CP-violating type-I 2HDM

The Large Hadron Collider is shown to have great scope for a light charged Higgs discovery, in the context of the CP-violating type-I two Higgs doublet model. This scenario with similar masses of $H^\pm$ and W was suggested by the puzzling departure from charged current lepton universality found in the LEP data. With the lightest neutral Higgs mass set to 125 GeV, the charged-neutral Higgs associated production mechanism can cause a significant excess in the $τνb \bar{b}$ events over a vast range of tan beta as long as the Higgs mixing pattern avoids a few limiting cases. Thanks to the low $H^\pm$ mass, the charged Higgs loop can play a striking role in neutral Higgs decays into $γγ$, thereby compensating for a suppressed gluon-gluon fusion rate. The effect of scalar-pseudo-scalar mixing on loop-induced Higgs signals is also discussed.

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arXiv2012

Higgs-induced lepton flavor violation

Due to the smallness of the lepton Yukawa couplings, higher-dimensional operators can give a significant contribution to the lepton masses. In this case, the lepton mass matrix and the matrix of lepton-Higgs couplings are misaligned leading to lepton flavor violation (LFV) mediated by the Standard Model Higgs boson. We derive model-independent bounds on the Higgs flavor violating couplings and quantify LFV in decays of leptons and electric dipole moments for a class of lepton-Higgs operators contributing to lepton masses. We find significant Higgs-mediated LFV effects at both 1-loop and 2-loop levels.

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