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Dong-Won Jung

Publications and source records attributed to Dong-Won Jung.

At least 37 records · Page 2Linked to original sources
arXiv2012

Dynamical Symmetry Breaking in Supersymmetric Extensions of Nambu-Jona-Lasinio Model

In this paper we discuss Nambu-Jona-Lasinio model as a classical model for dynamical mass generation and symmetry breaking. In addition we discuss the possible supersymmetric extensions of this model resulting from interaction terms with four chiral superfields that may be regarded as a supersymmetric generalization of the four-fermion interactions of the Nambu-Jona-Lasinio model. A four-superfield interaction terms can be constructed as either dimension 6 or dimension 5 operators. Through analyzing solutions to the gap equations, we discuss the dynamical generation of superfield Dirac mass, including a supersymmetry breaking part. A dynamical symmetry breaking generally goes along with the dynamical mass generation, for which a bi-superfield condensate is responsible.

hep-th↗
arXiv2012

Dynamical Symmetry Breaking with Four-Superfield Interactions

We investigate the dynamical mass generation resulted from interaction terms with four chiral superfields. The kind of interactions maybe considered a supersymmetric generalization of the four-fermion interactions of the classic Nambu--Jona-Lasinio model. A four-superfield interaction that contains a four-fermion interaction as one of its component terms has been the standard supersymmetrization of the NJL model for decades. Recently, we introduced a holomorphic variant with a dimension five interaction term instead. The latter is a main target of the present analysis. With the introduction of a new perspective on the superfield gap equation, we derive it for each one of the four-superfield interactions, using the supergraph technique. Through analyzing solutions to the gap equations, we illustrate the dynamical generation of superfield Dirac mass, including a supersymmetry breaking part. A dynamical symmetry breaking generally goes along with the dynamical mass generation, for which a bi-superfield condensate is responsible. The explicit illustration of dynamical symmetry breaking from the holomorphic dimension five interaction is reported for the first time. It has rich and novel features, which would be easily missed without the superfield approach developed here. We also discuss the nature of the bi-superfield condensate and its role of the effective Higgs superfield picture for both cases, illustrating their difference. Note that such a holomorphic quark superfield interaction term can successful account for the electroweak symmetry breaking with Higgs superfields as composites.

hep-th↗
arXiv2012

Mass dependent top forward backward asymmetry in the effective Lagrangian approach: Addendum to "Model independent analysis of the forward-backward asymmetry of top quark production at the Tevatron"

Recently the CDF and the D0 Collaborations presented the data on the top forward-backward (FB) asymmetry A_FB as functions of M_(t t^bar) and Δy = y_t - y_t^bar. We study these observables in the effective Lagrangian approach with dimension-6 q q^bar t t^bar contact interactions, and compare with the CDF and D0 data. When we stay within the validity region of the effective Lagrangian approach, the mass dependent top FB asymmetry turns out to be smaller than the CDF data, more than 2-sigma away. If this discrepancy remains in the future data with better statistics, it would imply that the effective Lagrangian approach is not adequate for the top FB asymmetry, and a new physics scale around a few hundred GeV in the t- or u-channel may be responsible for the observed top FB asymmetry.

hep-ph↗
arXiv2011

Possible Common Origin of the Top Forward-backward Asymmetry and the CDF Dijet Resonance

A color-singlet neutral vector boson is considered as a possible common origin of the top forward-backward asymmetry and the CDF dijet resonance. We identify chiral and flavor structures of the couplings of this new vector boson to the standard model quarks for which one could accommodate both data. We also demonstrate that non-vanishing observables involving longitudinal top polarizations can provide useful criteria for the possible existence of parity violating new physics in the q q^bar -> t t^bar process, and discrimination between the flavor-conserving and flavor-violating cases.

hep-ph↗
arXiv2011

Longitudinal top polarization as a probe of a possible origin of forward-backward asymmetry of the top quark at the Tevatron

If the forward-backward (FB) asymmetry of top quark ($A_{\rm FB}$) observed at the Tevatron deviates from the SM prediction, there must be $P$-violating interactions in $q\bar{q} \rightarrow t\bar{t}$. This new interaction will necessarily affect the top spin polarization. In this letter, we perform a model independent analysis on the longitudinal (anti)top polarization ($P_L$ and $\bar{P}_L$) using an effective lagrangian with dim-6 four-quark operators relevant for $q \bar{q} \rightarrow t \bar{t}$, and show that the $P$-odd observable corresponding to the polarization difference $(P_L - \bar{P}_L)$ gives important informations on the chiral structures of new physics that might be relevant to the $A_{\rm FB}$.

hep-ph↗
arXiv2011

Electroweak symmetry breaking and cold dark matter from strongly interacting hidden sector

We consider a hidden sector with a vectorlike confining gauge theory like QCD with $N_{h,c}$ colors and $N_{h,f}$ light quarks ${\cal Q}_h$ in the hidden sector. Then a scale $Λ_H$ would be generated by dimensional transmutation, and chiral symmetry breaking occurs in the hidden sector. This scale $Λ_H$ can play a role of the SM Higgs mass parameter, triggering electroweak symmetry breaking (EWSB). Furthermore the lightest mesons in the hidden sector is stable by flavor conservation of the hidden sector strong interaction, and could be a good cold dark matter (CDM). We study collider phenomenology, and relic density and direct detection rates of the CDM of this model.

hep-ph↗
arXiv2010

Model independent analysis of the forward-backward asymmetry of top quark production at the Tevatron

Motivated by a possible anomaly in the forward-backward (FB) asymmetry of top quark (A_{\rm FB}) observed at the Tevatron, we perform a model independent analysis on q \bar{q} \to t \bar{t} using an effective lagrangian with dim-6 four-quark operators. We derive necessary conditions on new physics structures and the couplings that are consistent with the t\bar{t} production cross section and A_{\rm FB} measured at the Tevatron, and discuss possible new physics scenarios that could generate such dim-6 operators.

hep-ph↗
arXiv2009

AMSB Demystified

We reinterpret anomaly-mediated supersymmetry breaking from a field-theoretic perspective in which superconformal anomalies couple to either the chiral compensator or the $U(1)_R$ vector superfield. As supersymmetry in the hidden sector is spontaneously broken by non-vanishing vacuum expectation values of the chiral compensator F-term and/or the $U(1)_R$ vector superfield D-term, the soft breakdown of supersymmetry emerges in the visible sector. This approach is physically more understandable compared with the conventional approach where the chiral compensator is treated on the same footing as a spurion in gauge-mediated supersymmetry breaking scenario.

hep-ph↗
arXiv2009

Anomaly-Mediated Supersymmetry Breaking Demystified

We reinterpret anomaly-mediated supersymmetry breaking from a field-theoretic perspective in which superconformal anomalies couple to either the chiral compensator or the $U(1)_R$ vector superfield. As supersymmetry in the hidden sector is spontaneously broken by non-vanishing vacuum expectation values of the chiral compensator F-term and/or the $U(1)_R$ vector superfield D-term, the soft breakdown of supersymmetry emerges in the visible sector. This approach is physically more understandable compared with the conventional approach where the chiral compensator is treated on the same footing as a spurion in gauge-mediated supersymmetry breaking scenario.

hep-ph↗
arXiv2008

Exploring the charged Higgs bosons in the lef-right symmetric model

We explore constraints on the charged Higgs sector in the left-right (LR) model from the present experimental data. Due to the different Yukawa structure, the allowed parameter space of the charged Higgs boson in the LR model is different from that in the two Higgs doublet model. We find that the constraint from $t \to b H^\pm$ decay at Tevatron is most significant, while $B \to τν$ decay could provide no constraint on the LR model. Bounds from $e^- e^+ \to H^- H^+$ process at LEP are similar to that in the two Higgs doublet model.

hep-ph↗
arXiv2007

1-loop Corrections to the ρParameter in the Left-Right Twin Higgs Model

We implement a one-loop analysis of the $ρ$ parameter in the Left Right Twin Higgs model, including the logarithmically enhanced contributions from both fermion and scalar loops. Numerical results show that the one-loop contributions are dominant over the tree level corrections in most regions of parameter space. The experimentally allowed values of $ρ$-parameter divide the allowed parameter space into two regions; less than $670 {\rm GeV}$ and larger than $1100 {\rm GeV}$ roughly, for symmetry breaking scale $f$. Our numerical analysis significantly reduces the parameter space which are favorably accessible to the LHC.

hep-ph↗
arXiv2006

Partially composite 2-Higgs-doublet model

In the extra dimensional scenarios with gauge fields in the bulk, the Kaluza-Klein (KK) gauge bosons can induce Nambu-Jona-Lasinio (NJL) type attractive four-fermion interactions, which can break electroweak symmetry dynamically with accompanying composite Higgs fields. We consider a possibility that electroweak symmetry breaking (EWSB) is triggered by both a fundamental Higgs and a composite Higgs arising in a dynamical symmetry breaking mechanism induced by a new strong dynamics. The resulting Higgs sector is a partially composite two-Higgs doublet model with specific boundary conditions on the coupling and mass parameters originating at a compositeness scale $Λ$. The phenomenology of this model is discussed including the collider phenomenology at LHC and ILC.

hep-ph↗
arXiv2005

Partially composite two-Higgs doublet model

In the extra dimensional scenarios with gauge fields in the bulk, the Kaluza-Klein (KK) gauge bosons can induce Nambu-Jona-Lasinio (NJL) type attractive four-fermion interactions, which can break electroweak symmetry dynamically with accompanying composite Higgs fields. We consider a possibility that electroweak symmetry breaking (EWSB) is triggered by both a fundamental Higgs and a composite Higgs arising in a dynamical symmetry breaking mechanism induced by a new strong dynamics. The resulting Higgs sector is a partially composite two-Higgs doublet model with specific boundary conditions on the coupling and mass parameters originating at a compositeness scale $Λ$. The phenomenology of this model is discussed including the collider phenomenology at LHC and ILC.

hep-ph↗
arXiv2004

CP violation in associated charged Higgs boson production with a single top at the LHC

We explore the CP violation in the charged Higgs production associated with a top quark at the LHC in the MSSM. The supersymmetric phases of gaugino masses and trilinear $A$ terms lead to a CP violating asymmetry of the cross section in the $ p p \to g b \to t H^\pm$ process through loop corrections to the $tbH^\pm$ vertex. We find that a CP violation more than 10 % is possible if the charged Higgs boson is heavy enough.

hep-ph↗
arXiv2004

Neutrino Oscillations and Collider Test of the R-parity Violating mSUGRA Model

We study the R-parity violating minimal supergravity models accounting for the observed neutrino masses and mixing, which can be tested in future collider experiments. The bi-large mixing can be explained by allowing five dominant tri-linear couplings $ λ'_{1,2,3}$ and $λ_{1,2}$. The desired ratio of the atmospheric and solar neutrino mass-squared differences can be obtained in a very limited parameter space where the tree-level contribution is tuned to be suppressed. In this allowed region, we quantify the correlation between the three neutrino mixing angles and the tri-linear R-parity violating couplings. Such a prediction on the couplings can be tested in the next linear colliders by observing the branching ratios of the lightest supersymmetric particle (LSP). For the stau or the neutralino LSP, the ratio $|λ_1|^2: |λ_2|^2: |λ_1|^2 + |λ_2|^2$ can be measured by establishing $Br(eν): Br(μν) : Br(τν)$ or $Br(νe^\pm τ^\mp): Br(νμ^\pmτ^\mp) : Br(ντ^\pmτ^\mp)$, respectively. The information on the couplings $λ'_i$ can be drawn by measuring $Br(l_i t \bar{b}) \propto |λ'_i|^2$ if the neutralino LSP is heavier than the top quark.

hep-ph↗
arXiv2004

Neutrino Oscillations and Collider Test of the R-parity Violating Minimal Supergravity Model

We study the R-parity violating minimal supergravity models accounting for the observed neutrino masses and mixing, which can be tested in future collider experiments. The bi-large mixing can be explained by allowing five dominant tri-linear couplings $ λ'_{1,2,3}$ and $λ_{1,2}$. The desired ratio of the atmospheric and solar neutrino mass-squared differences can be obtained in a very limited parameter space where the tree-level contribution is tuned to be suppressed. In this allowed region, we quantify the correlation between the three neutrino mixing angles and the tri-linear R-parity violating couplings. Qualitatively, the relations $| λ'_1 | < | λ'_2| \sim | λ'_3|$, and $|λ_1| \sim |λ_2|$ are required by the large atmospheric neutrino mixing angle $θ_{23}$ and the small angle $θ_{13}$, and the large solar neutrino mixing angle $θ_{12}$, respectively. Such a prediction on the couplings can be tested in the next linear colliders by observing the branching ratios of the lightest supersymmetric particle (LSP). For the stau or the neutralino LSP, the ratio $|λ_1|^2: |λ_2|^2: |λ_1|^2 + |λ_2|^2$ can be measured by establishing $Br(eν): Br(μν) : Br(τν)$ or $Br(νe^\pm τ^\mp ): Br(νμ^\pmτ^\mp) : Br(ντ^\pmτ^\mp)$, respectively. The information on the couplings $λ'_i$ can be drawn by measuring $Br(l_i t \bar{b}) \propto |λ'_i|^2$ if the neutralino LSP is heavier than the top quark.

hep-ph↗
arXiv2003

Neutrino Mass Matrix in the Minimal Supergravity Model: Bi-large Mixing with Trilinear R-parity Violation

We study the correlation between the neutrino oscillation and the production/decay of the lightest supersymmetric particle(LSP) in the context of the minimal supergravity model(mSUGRA) without R-parity. We show how the neutrino masses and mixing which are consistent with the recent neutrino data can be obtained in this model, and describe how to probe the model by observing the LSP decay at collider experiments. It is shown that the generic 1-loop contributions to neutrino masses are too small to account for the solar and atmospheric neutrino oscillations and thus some fine cancellation in tree-level contribution is required to severely constrain the viable parameter space. In most parameter space of mSUGRA, the neutralino or the stau is LSP. Examining both cases, we find that there is a simple correlation between the neutrino mixing angles and the LSP branching ratios in the small $\tanβ$ region so that the model can be clearly tested in the future colliders. In the large $\tanβ$ region, such a correlation is obscured by the large tau Yukawa contribution which makes it nontrivial to test the model.

hep-ph↗