arXiv subjects

Warintorn Sreethawong

Publications and source records attributed to Warintorn Sreethawong.

16 recordsLinked to original sources

arXiv2025

Radiative decay of $χ_{c1}$ states in effective Lagrangian approach

The $χ_{c1}(3872)$ state, first observed by the Belle collaboration with its quantum numbers identified as $J^{PC} = 1^{++}$, has been the subject of extensive research due to its intriguing properties. Several theoretical interpretations have been proposed to explain its unique characteristics, including the $χ_{c1}(2P)$ assignment, a molecular $\bar{D}^{*}D/\bar{D}D^{*}$ configuration, a coupled-channel framework incorporating $c\bar{c}$ and di-meson degrees of freedom, and the compact tetraquark hypothesis. However, challenges remain in reconciling its mass coincidence with the threshold and the observed isospin violation within both the pure $c\bar{c}$ and compact tetraquark models. In this study, we examine the radiative decays of the $χ_{c1}(1P)$ and $χ_{c1}(3872)$ states in an effective field theory framework, incorporating triangle loops of $D$ and $D^{*}$ mesons. The model parameters are calibrated based on the observed branching fraction of the radiative decay mode $χ_{c1}(1P) \to J/ψγ$. Utilizing these fixed parameters, we predict the branching fractions $R_{χ_{c1}(3872) \to J/ψγ} \sim 10^{-1}$ and $R_{χ_{c1}(3872) \to ψ(2S) γ} \sim 10^{-2}$, and the relative fraction $\mathcal{R}_{Ψγ} \approx 0.109$. The work supports the argument that the $χ_{c1}(3872)$ is unlikely a $c\bar{c}$ state.

hep-ph↗

arXiv2024

Determining the Meson Cloud Contribution of Nucleon Electromagnetic Form Factor Using Dispersion Relation

We explore the meson cloud contribution to nucleon electromagnetic form factors in dispersion relation approach. In our calculations, experimental data on transition amplitudes for pion-nucleon scatterings are taken directly as inputs, with the assumption that the photon-pion interaction dominates over other meson-photon couplings. Combining with the quark core contribution evaluated in quark model, the proton electromagnetic form factors are well reproduced in the work. The resulting mean-square charge radius of the proton agrees well with experimental data, and the quark core radius is reasonable.

hep-ph↗

arXiv2024

Neutrino Oscillation Effects on the Luminosity of Neutrino-Dominated Accretion Flows Around Black Holes

The stellar-mass black hole surrounded by the neutrino-dominated accretion flow (NDAF) is proposed to be the central engine of the gamma-ray burst (GRB). In this work, we investigate the neutrino/anti-neutrino luminosity and annihilation luminosity from the NDAF and pair-annihilation model, taking into account the neutrino oscillation above the accretion disk. The disk hydrodynamical properties are modelled using the empirical solution previously derived with boundary conditions including the effect of electron degeneracy and neutrino trapping. Our key parameters are the mass accretion rate and the black hole spin given in the range of $\dot{M} = 0.1$ - $10$ $M_\odot$ s$^{-1}$ and $ 0 \le a < 1$, respectively. Without neutrino oscillation, the obtained neutrino/anti-neutrino luminosity is $\sim 10^{51}$ - $10^{53}$ $\textrm{erg s}^{-1}$, while the neutrino annihilation luminosity is found to be $\sim 10^{46}$ - $10^{51}$ $\textrm{erg s}^{-1}$. In the presence of neutrino oscillation in the vacuum limit, the electron neutrino annihilation luminosity decreases by $\lesssim 22\%$ through the flavor transformation, while the muon- and tau-neutrino luminosity can increase up to $\sim 45\%$ and $ 60\%$, respectively. As a result, the total annihilation luminosity can be reduced up to $\sim 19\%$ due to the oscillation process above the disk. Finally, we also investigate the case whereby the CP-violating phase is changed from $δ\textrm{CP} =$ $0^{\circ}$ to $245^{\circ}$. However, our results reveal that the CP-violating phase has minimal impact on neutrino annihilation luminosity.

astro-ph.HE↗

arXiv2024

Mass spectrum of $1^{--}$ heavy quarkonium

We calculate the masses and leptonic decay widths of the bottomonium $b\bar b$ and charmonium $c\bar c$ states in a constituent quark model where the Cornell-like potential and spin-dependent interaction are employed, with all model parameters predetermined by studying ground and first radial excited states of S- and P-wave heavy quarkonium mesons. By comparing the theoretical predictions for $J^{PC}=1^{--}$ quarkonium states with experimental data and considering possible mixtures of $nS$ and $(n-1)D$ states, we provide tentative assignments for all observed $J^{PC}=1^{--}$ heavy quarkonia. The work suggests that the $Υ$(10860) and $Υ$(11020) are $b\bar b$ $5S-4D$ mixture states, and the $ψ$(4360) and $ψ$(4415) are largely $4S$ and $3D$ $c\bar c$ states respectively. The $ψ$(4260) may not be accommodated with the conventional meson picture in the present work.

hep-ph↗

arXiv2023

Vacuum Stability and Radiative Symmetry Breaking of the Scale-Invariant Singlet Extension of Type II Seesaw Model

The questions of the origin of electroweak symmetry breaking and neutrino mass are two major puzzles in particle physics. Neutrino mass generation requires new physics beyond the Standard Model and also suggests reconsideration of physics of symmetry breaking. The aim of this paper is to study radiative symmetry breaking in the singlet scalar extension of type II seesaw neutrino mass model. We derive bounded-from-below conditions for the scalar potential of the model in full generality for the first time. The Gildener-Weinberg approach is utilised in minimising the multiscalar potential. Upon imposing the bounded-from-below and perturbativity conditions, as well as experimental constraints from colliders, we find the parameter space of scalar quartic couplings that can radiatively realise electroweak symmetry breaking at one-loop level. To satisfy all the constraints, the masses of the heavy triplet-like Higgs bosons must be nearly degenerate. The evolution of the Higgs doublet quartic coupling $λ_{H}$ can be prevented from being negative up to the Planck scale.

hep-ph↗

arXiv2022

Estimation of coupling constants for D-meson, charmed, and light baryons in effective Lagrangian approach and quark model

We estimate coupling constants for effective Lagrangians of $D$-meson, charmed, and light baryons from charmed baryon decay processes. First, we calculate decay widths for the processes $Λ_{c} \to DN$, $Σ_{c} \to D Δ$, $Σ_{c} \to D^{*} Δ$, and $Λ_{c} \to D^{*}N$ in effective Lagrangian method and quark model picture with $^{3}P_{0}$ model. By employing the coupling constants for $D^{*} Λ_{c} N$ interaction from several literatures, the strength parameter $λ$ for $^{3}P_{0}$ quark model is fixed in the decay process $Λ_{c} \to D^{*}N$. Then, the coupling constants for the effective Lagrangians of $DΛ_{c}N$, $DΣ_{c}Δ$, and $D^{*}Σ_{c}Δ$ interactions are estimated in the decay channels $Λ_{c} \to DN$, $Σ_{c} \to D Δ$, and $Σ_{c} \to D^{*} Δ$, respectively. These coupling constants will be useful for further studies of charm hadrons.

hep-ph↗

arXiv2015

Same sign diboson signature from supersymmetry models with light higgsinos at the LHC

In supersymmetric models with light higgsinos (which are motivated by electroweak naturalness arguments), the direct production of higgsino pairs may be difficult to search for at LHC due to the low visible energy release from their decays. However, the wino pair production reaction \tw_2^\pm\tz_4\to (W^\pm\tz_{1,2})+(W^\pm\tw_1^\mp) also occurs at substantial rates and leads to final states including equally opposite-sign (OS) and same-sign (SS) diboson production. We propose a novel search channel for LHC14 based on the SS diboson plus missing E_T final state which contains only modest jet activity. Assuming gaugino mass unification, and an integrated luminosity > 100 fb^{-1}, this search channel provides a reach for SUSY well beyond that from usual gluino pair production.

hep-ph↗

arXiv2015

Radiatively-driven natural supersymmetry at the LHC

Radiatively-driven natural supersymmetry (RNS) potentially reconciles the Z and Higgs boson masses close to 100 GeV with gluinos and squarks lying beyond the TeV scale. Requiring no large cancellations at the electroweak scale in constructing M_Z=91.2 GeV while maintaining a light Higgs scalar with m_h 125 GeV implies a sparticle mass spectrum including light higgsinos with mass 100-300 GeV, electroweak gauginos in the 300-1200 GeV range, gluinos at 1-4 TeV and top/bottom squarks in the 1-4 TeV range (probably beyond LHC reach), while first/second generation matter scalars can exist in the 5-30 TeV range (far beyond LHC reach). We investigate several characteristic signals for RNS at LHC14. Gluino pair production yields a reach up to m_{\tg} 1.7 TeV for 300 fb^{-1}. Wino pair production -- pp\to\tw_2\tz_4 and \tw_2\tw_2 -- leads to a unique same-sign diboson (SSdB) signature accompanied by modest jet activity from daughter higgsino decays; this signature provides the best reach up to m_{\tg} 2.1 TeV within this framework. Wino pair production also leads to final states with (WZ\to 3\ell)+\eslt as well as 4\ell+\eslt which give confirmatory signals up to m_{\tg} 1.4 TeV. Directly produced light higgsinos yield a clean, soft trilepton signature (due to very low visible energy release) which can be visible, but only for a not-too-small a \tz_2-\tz_1 mass gap. The clean SSdB signal -- as well as the distinctive mass shape of the dilepton mass distribution from \tz_{2,3}\to\tz_1\ell\ell decays if this is accessible -- will mark the presence of light higgsinos which are necessary for natural SUSY. While an e^+e^- collider operating with \sqrt{s} 600 GeV should unequivocally reveal the predicted light higgsinos, the RNS model with m_{1/2}> 1 TeV may elude all LHC14 search strategies even while maintaining a high degree of electroweak naturalness.

hep-ph↗

arXiv2013

Leaving no stone unturned in the hunt for SUSY naturalness: A Snowmass whitepaper

Imposing electroweak scale naturalness constraints (low Δ_{EW}) on SUSY models leads to mass spectra characterized by light higgsinos ~100-300 GeV, highly mixed top-squarks and gluinos at the 1-5 TeV scale and allows for m_h ~125 GeV. First and second generation squarks can easily live at the 5-20 TeV scale, thus providing at least a partial solution to the SUSY flavor/CP problems. For such models at the LHC, gluino pair production is followed by cascade decays to t- and b-quark rich final states along with multileptons. The reach of LHC14 with 300 fb^{-1} is computed to be around m_{\tg} 1.8 TeV. However, the small magnitude of the μ-parameter-- a necessary condition for naturalness-- leads to a unique hadronically quite same-sign diboson (W^\pm W^\pm) signature from wino pair production. In low Δ_{EW} models with unified gaugino masses, this signature yields a somewhat higher reach up to m_{\tg} 2.1 TeV. The smallness of |μ| implies that the ILC should be a higgsino factory in addition to a Higgs factory, and a complete search for SUSY naturalness seems possible for \sqrt{s} 600 GeV. Since a thermal under-abundance of higgsino-like WIMP dark matter (DM) is expected, there is ample room for an axion DM contribution. A thorough search for higgsino-like WIMPs can be made by next generation WIMP detectors, such as those with ton-scale noble liquid targets.

hep-ph↗

arXiv2012

WZ plus missing-E_T signal from gaugino pair production at LHC7

LHC searches for supersymmetry currently focus on strongly produced sparticles, which are copiously produced if gluinos and squarks have masses of a few hundred GeV. However, in supersymmetric models with heavy scalars, as favored by the decoupling solution to the SUSY flavor and CP problems, and m_{\tg}> 500 GeV as indicated by recent LHC results, chargino--neutralino (\tw_1^\pm\tz_2) production is the dominant cross section for m_{\tw_1} \sim m_{\tz_2} < m_{\tg}/3 at LHC with \sqrt{s}=7 TeV (LHC7). Furthermore, if m_{\tz_1}+m_Z \lesssim m_{\tz_2}\lesssim m_{\tz_1}+m_h, then \tz_2 dominantly decays via \tz_2\to\tz_1 Z, while \tw_1 decays via \tw_1\to \tz_1 W. We investigate the LHC7 reach in the WZ + MET channel (for both leptonic and hadronic decays of the W boson) in models with and without the assumption of gaugino mass universality. In the case of the mSUGRA/CMSSM model with heavy squark masses, the LHC7 discovery reach in the WZ+MET channel becomes competetive with the reach in the canonical MET + jets channel for integrated luminosities \sim 30 fb^-1. We also present the LHC7 reach for a simplified model with arbitrary m_{\tz_1} and m_{\tw_1} \sim m_{\tz_2}. Here, we find a reach of up to m_{\tw_1}\sim 200 (250) GeV for 10 (30) fb^-1.

hep-ph↗

arXiv2012

Wh plus missing-E_T signature from gaugino pair production at the LHC

In SUSY models with heavy squarks and gaugino mass unification, the gaugino pair production reaction pp-> \tw_1^\pm\tz_2 dominates gluino pair production for m_{\tg}\agt 1 TeV at LHC with \sqrt{s}=14 TeV (LHC14). For this mass range, the two-body decays \tw_1\to W\tz_1 and \tz_2\to h\tz_1 are expected to dominate the chargino and neutralino branching fractions. By searching for \ell b\bar{b}+MET events from \tw_1^\pm\tz_2 production, we show that LHC14 with 100 fb^{-1} of integrated luminosity becomes sensitive to chargino masses in the range m_{\tw_1}\sim 450-550 GeV corresponding to m_{\tg}\sim 1.5-2 TeV in models with gaugino mass unification. For 10^3 fb^{-1}, LHC14 is sensitive to the Wh channel for m_{\tw_1}\sim 300-800 GeV, corresponding to m_{\tg}\sim 1-2.8 TeV, which is comparable to the reach for gluino pair production followed by cascade decays. The Wh+MET search channel opens up a new complementary avenue for SUSY searches at LHC, and serves to point to SUSY as the origin of any new physics discovered via multijet and multilepton + MET channels.

hep-ph↗

arXiv2011

Coupled Boltzmann calculation of mixed axion/neutralino cold dark matter production in the early universe

We calculate the relic abundance of mixed axion/neutralino cold dark matter which arises in R-parity conserving supersymmetric (SUSY) models wherein the strong CP problem is solved by the Peccei-Quinn (PQ) mechanism with a concommitant axion/saxion/axino supermultiplet. By numerically solving the coupled Boltzmann equations, we include the combined effects of 1. thermal axino production with cascade decays to a neutralino LSP, 2. thermal saxion production and production via coherent oscillations along with cascade decays and entropy injection, 3. thermal neutralino production and re-annihilation after both axino and saxion decays, 4. gravitino production and decay and 5. axion production both thermally and via oscillations. For SUSY models with too high a standard neutralino thermal abundance, we find the combined effect of SUSY PQ particles is not enough to lower the neutralino abundance down to its measured value, while at the same time respecting bounds on late-decaying neutral particles from BBN. However, models with a standard neutralino underabundance can now be allowed with either neutralino or axion domination of dark matter, and furthermore, these models can allow the PQ breaking scale f_a to be pushed up into the 10^{14}-10^{15} GeV range, which is where it is typically expected to be in string theory models.

hep-ph↗

arXiv2011

Mixed axion/neutralino cold dark matter in supersymmetric models

We consider supersymmetric (SUSY) models wherein the strong CP problem is solved by the Peccei-Quinn (PQ) mechanism with a concommitant axion/axino supermultiplet. We examine R-parity conserving models where the neutralino is the lightest SUSY particle, so that a mixture of neutralinos and axions serve as cold dark matter. The mixed axion/neutralino CDM scenario can match the measured dark matter abundance for SUSY models which typically give too low a value of the usual thermal neutralino abundance, such as models with wino-like or higgsino-like dark matter. The usual thermal neutralino abundance can be greatly enhanced by the decay of thermally-produced axinos to neutralinos, followed by neutralino re-annihilation at temperatures much lower than freeze-out. In this case, the relic density is usually neutralino dominated, and goes as \sim (f_a/N)/m_{axino}^{3/2}. If axino decay occurs before neutralino freeze-out, then instead the neutralino abundance can be augmented by relic axions to match the measured abundance. Entropy production from late-time axino decays can diminish the axion abundance, but ultimately not the neutralino abundance. In mixed axion/neutralino CDM models, it may be possible to detect both a WIMP and an axion as dark matter relics. We also discuss possible modifications of our results due to production and decay of saxions. In the appendices, we present expressions for the Hubble expansion rate and the axion and neutralino relic densities in radiation, matter and decaying-particle dominated universes.

hep-ph↗

arXiv2010

Testing the gaugino AMSB model at the Tevatron via slepton pair production

Gaugino AMSB models-- wherein scalar and trilinear soft SUSY breaking terms are suppressed at the GUT scale while gaugino masses adopt the AMSB form-- yield a characteristic SUSY particle mass spectrum with light sleptons along with a nearly degenerate wino-like lightest neutralino and quasi-stable chargino. The left- sleptons and sneutrinos can be pair produced at sufficiently high rates to yield observable signals at the Fermilab Tevatron. We calculate the rate for isolated single and dilepton plus missing energy signals, along with the presence of one or two highly ionizing chargino tracks. We find that Tevatron experiments should be able to probe gravitino masses into the ~55 TeV range for inoAMSB models, which corresponds to a reach in gluino mass of over 1100 GeV.

hep-ph↗

arXiv2010

Search for the Elusive Higgs Boson Using Jet Structure at LHC

We consider the production of a light non-standard model Higgs boson of order $100~\GEV$ with an associated $W$ boson at CERN Large Hadron Collider. We focus on an interesting scenario that, the Higgs boson decays predominately into two light scalars $χ$ with mass of few GeV which sequently decay into four gluons, i.e. $h\to 2χ\to 4g$. Since $χ$ is much lighter than the Higgs boson, it will be highly boosted and its decay products, the two gluons, will move close to each other, resulting in a single jet for $χ$ decay in the detector. By using electromagnetic calorimeter-based and jet substructure analyses, we show in two cases of different $χ$ masses that it is quite promising to extract the signal of Higgs boson out of large QCD background.

hep-ph↗

arXiv2009

Discriminating Electroweak-ino Parameter Ordering at the LHC and Its Impact on LFV Studies

Current limit on the dark matter relic abundance may suggest that $|μ|$ should be smaller than prediction in the minimal supergravity scenario (mSUGRA) for moderate $m_0$ and $m_{1/2}$. The electroweak-ino parameter $M_1, M_2$ and $|μ|$ are then much closer to each other. This can be realized naturally in the non-universal Higgs mass model (NUHM). Since the heaviest neutralino ($\tildeχ^0_4$) and chargino ($\tildeχ^\pm_2$) have significant gaugino components, they may appear frequently in the left-handed squark decay and then be detectable at the LHC. In such a case, we showed that the hierarchy of $M_1, M_2$ and $|μ|$ can be determined. In the light slepton mass scenario with non-vanishing lepton-flavor violation (LFV) in the right-handed sector, NUHM with small $|μ|$ corresponds to region of parameter space where strong cancellation among leading contributions to $Br(μ\to eγ)$ can occur. We showed that determination of electroweak-ino hierarchy plays a crucial role in resolving cancellation point of $Br(μ\to eγ)$ and determination of LFV parameters. We also discussed test of the universality of the slepton masses at the LHC and the implications to SUSY flavor models.

hep-ph↗