The rare decay channels of Higgs boson to heavy quarkonium offer vital opportunities to explore the coupling of Higgs to heavy quarks. We study the semi-exclusive decay channels of Higgs boson to heavy quarkonia, i.e., $H^0\to |(Q\bar{Q^{\prime}})[n]\rangle+\bar{Q}Q^{\prime}$ ($Q^{(\prime)}=c~\text{or}~b$ quark) within the NRQCD framework. In addition to the lower-level Fock states $|(Q\bar{Q'})[1S]\rangle$ continent, contributions of high excited states $|(Q\bar{Q'})[2S]\rangle$, $|(Q\bar{Q'})[3S]\rangle$, $|(Q\bar{Q'})[4S]\rangle$, $|(Q\bar{Q'})[1P]\rangle$, $|(Q\bar{Q'})[2P]\rangle$, $|(Q\bar{Q'})[3P]\rangle$ and $|(Q\bar{Q'})[4P]\rangle$ are also studied. According to our study, the contributions of high excited Fock states should be considered seriously. Differential distributions of total decay width with respect to invariant-mass and angles, as well as uncertainties caused by non-perturbative hadronic non-perturbative matrix elements are discussed. If all excited heavy quarkonium states decay to the ground spin-singlet state through electromagnetic or hadronic interactions, we obtain the decay widths for $|(Q\bar{Q'})\rangle$ quarkonium production through $H^0$ semi-exclusive decays: $25.10^{+11.6\%}_{-51.6\%}$ keV for $|(b\bar{c})[n]\rangle$ meson, $3.23^{+0\%}_{-62.2\%}$ keV for $|(c\bar{c})[n]\rangle$ and $2.36^{+0\%}_{-57.1\%}$ keV for $|(b\bar{b})[n]\rangle$, where uncertainties are caused by adopting different non-perturbative potential models. At future high energy LHC ($\sqrt{s}=27$ TeV), numerical results show that sizable amounts of events for those high excited states can be produced, which implies that one could also consider exploring the coupling properties of Higgs to heavy quarks in these high excited states channels, especially for the charmonium and bottomonium.
A leptonic $(\bar l l)$ decay of a heavy quark-antiquark bound state $T(\bar QQ)$ with a Higgs-boson $H$ emission is investigated. The applying of the well-known low-energy theorem to meson-Higgs coupling allows one to estimate the probability of the decay $T(\bar QQ)\to \bar ll H$. The only a simple version of the Standard Model extension containing two-Higgs doublet is considered.
We point out that the determination of the leptonic decay width of radially-excited quarkonia is strongly dependent on the position of the node typical of these excitations. We suggest that this feature could be related with the longstanding rho-pi puzzle.
In this addendum to Phys.\ Rev.\ D {\bf 95}, 054018 (2017) we recompute the rates for the decays of the Higgs boson to a vector quarkonium plus a photon, where the vector quarkonium is $J/ψ$, $Υ(1S)$, $Υ(2S)$, or $Υ(3S)$. We correct an error in the Abel-Padé summation formula that was used to carry out the evolution of the quarkonium light-cone distribution amplitude in Phys.\ Rev.\ D {\bf 95}, 054018 (2017). We also correct an error in the scale of quarkonium wave function at the origin in Phys.\ Rev.\ D {\bf 95}, 054018 (2017) and introduce several additional refinements in the calculation.
Sizable amount of heavy-quarkonium events can be produced through $W$-boson decays at the LHC. Such channels will provide a suitable platform to study the heavy-quarkonium properties. The "improved trace technology", which disposes the amplitude ${\cal M}$ at the amplitude-level, is helpful for deriving compact analytical results for complex processes. As an important new application, in addition to the production of the lower-level Fock states $|(Q\bar{Q'})[1S]>$ and $|(Q\bar{Q'})[1P]>$, we make a further study on the production of higher-excited $|(Q\bar{Q'})>$-quarkonium Fock states $|(Q\ba…
The value of quarkonium wave function at the origin is an important quantity while studying many physical problems concerning a heavy quarkonium. This is because that it is widely used to evaluate the production and decay amplitudes of the heavy quarkonium within the effective filed theory framework, e.g., the non-relativistic QCD (NRQCD). In this paper, the value of the Schr${\rm \ddot{o}}$dinger radial wave function or its first nonvanishing derivative at zero quark-antiquark separation, i.e., $|(|c\bar{c})[n]\rangle$-, $|(|b\bar{c})[n]\rangle$-, and $|(b\bar{b})[n]\rangle$-quarkonium, have …
We investigate the SM Higgs decays into heavy quarkonia J/ψand Υin both color-singlet and color-octet mechanisms. It is found that in J/ψproduction the contribution through color-octet processes overwhelm that in color-singlet processes all the intermediate region M_Z<M_{H^0}<2 M_w and the fraction ratio is comparatively large, but in Υproduction the contribution through color-octet mechanism is negligible.
The exclusive production of double excited quarkonium is comprehensive studied, i.e., the production of double excitedcharmonium, double excited bottomonium, and double excited $Bc$-mesons via $e^+e^-\to γ^*/Z^0 \to|(Q\bar{Q'})[n]\rangle +|(Q'\bar{Q})[n']\rangle$ ($Q/Q'=c$- or $b$-quarks) at a future $Z$ factory under the nonrelativistic quantum chromodynamics framework, where the $[n]$~/$[n']$ represents the color-singlet heavy quarkonium states $[^1S_0]\rangle, ~[^3S_1]\rangle, ~[^1P_1]\rangle$, and $[^3P_J]\rangle$ ($J=0,1,2$). The "improved trace technology" is adopted for calculating the …
We study the potential of radiative decays of the Upsilon(1S) and of the phi mesons to search for a light pseudoscalar Higgs boson, proposed as a possible interpretation of Sigma+ --> p mu+mu- events observed by the HyperCP collaboration at Fermilab. We conclude that the detection of this signal should certainly be possible with the current CLEO Upsilon(1S) data, and is within the reach of KLOE in at least part of the range of couplings suggested by the HyperCP findings.
The 125 GeV resonance discovered at the LHC could be a heavy quarkonium, spin 0 pseudoscalar meson $ζ^0$. The decay rates of the $ζ^0$ meson resonance are calculated and compared to the standard model Higgs boson decay rates. The branching ratios and signal strengths for $ζ\rightarrowγγ$, $ζ\rightarrow Zγ$, $ζ\rightarrow ZZ^*$ and $ζ\rightarrow WW^*$ are approximately the same as the Higgs boson branching ratios and signal strengths. The decay rates for $ζ\rightarrowτ^+τ^-$, $ζ\rightarrow b\bar b$ and $ζ\rightarrow c\bar c$ are suppressed compared to the Higgs boson decay rates. Accurate branc…
We present a systematic study of the production of the heavy quarkonium, i.e., $|(c\bar{c})[n] \rangle$ , $|(b\bar{c})[n] \rangle$ (or $|(c\bar{b})[n] \rangle$), and $|(b\bar{b})[n] \rangle$ quarkonium [$|(Q\bar{Q'})[n]\rangle$ quarkonium for short], through $Z^0$ boson semi-exclusive decays with new parameters \cite{lx} for the heavy quarkonium under the framework of the NRQCD, where $[n]$ stands for $n^1S_0$, $n^3S_1$, $n^1P_0$, $n^3P_J$ ($n=1, \cdots, 6$; $J=(0, 1, 2)$). "Improved trace technology" is adopted to derive the simplified analytic expressions at the amplitude level, which shall …
The 125 GeV resonance discovered at the LHC could be a heavy quarkonium pseudoscalar meson. The diagonalization of the mass matrix of the isoscalar quarkonium states $|ζ>$ and $|ζ^{0'}>$ produces the states identified with the pseudoscalar heavy quarkonium mesons $ζ^0$ and $ζ^{0'}$. For a mixing angle $ϕ\sim 36\,^{\circ}$ the mass of the bound state pseudoscalar resonance $ζ^0$ is $m_{ζ^0}\sim 125$ GeV. The decay rates of the quarkonium $ζ^0$ meson are estimated and compared to the standard model Higgs boson predictions. The importance of determining the spin-parity of the 125 GeV resonance is…
In this paper, we investigate the decay of Higgs boson to $J/ψ(Υ)$ plus a photon based on NRQCD factorization. For the direct process, we calculate the decay width up to QCD NLO. We find that the decay width for process $H \to J/ψ(Υ)+ γ$ direct production at the LO is significantly reduced by the NLO QCD corrections. For the indirect process, we calculate the $H \to γ^\astγ$ with virtual $γ$ substantially decaying to $J/ψ(Υ)$, including all the SM Feynman diagrams. The decay width of indirect production is much larger than the direct decay width. Since it is very clean in experiment, the $H \t…
The production of the heavy quarkonium, i.e., $|(c\bar{b})[n]\rangle$ (or $|(b\bar{c})[n]\rangle$), $|(c\bar{c})[n]\rangle$, and $|(b\bar{b})[n]\rangle$- quarkonium [$|(Q\bar{Q'})[n]\rangle$-quarkonium for short], through Higgs $H^{0}$ boson semiexclusive decays is evaluated within the NRQCD framework, where $[n]$ stands for the production of the two color-singlet $S$-wave states, $|(Q\bar{Q'})[^1S_0]_{\textbf{1}} \rangle$ and $|(Q\bar{Q'})[^3S_1]_{\textbf{1}} \rangle$, the production of the four color-singlet $P$-wave states, i.e., $|(Q\bar{Q'})[^1P_0]_{\textbf{1}}\rangle$, $|(Q\bar{Q'})[^3P_…
We present a calculation of the rates for Higgs-boson decays to a vector heavy-quarkonium state plus a photon, where the heavy quarkonium states are the J/psi and the Upsilon(nS) states, with n=1, 2, or 3. The calculation is carried out in the light-cone formalism, combined with nonrelativistic QCD factorization, and is accurate at leading order in m_Q^2/m_H^2, where m_Q is the heavy-quark mass and m_H is the Higgs-boson mass. The calculation contains corrections through next-to-leading order in the strong-coupling constant alpha_s and the square of the heavy-quark velocity v, and includes a r…
We study phenomenologically the invariant mass spectra of scalar dipion states produced in cascade decays of excited $Υ$ and $ψ$, and $J/ψ$ decays into light vector meson. Dipion production amplitude is given as a product of the Born term and an effective scalar form factor written in terms of a unitarized chiral theory. The model reproduces the experimental mass spectra very well.
In Ref.[7],we have dealt with the production of the two color-singlet $S$-wave $(c\bar{b})$-quarkonium states $B_c(|(c\bar{b})_{\bf 1}[^1S_0]>)$ and $B^*_c(|(c\bar{b})_{\bf 1}[^3S_1]>)$ through the $Z^0$ boson decays. As an important sequential work, we make a further discussion on the production of the more complicated $P$-wave excited $(c\bar{b})$-quarkonium states, i.e. $|(c\bar{b})_{\bf 1}[^1P_1]>$ and $|(c\bar{b})_{\bf 1}[^3P_J]>$ (with $J=(1,2,3)$). More over, we also calculate the channel with the two color-octet quarkonium states $|(c\bar{b})_{\bf 8}[^1S_0]g>$ and $|(c\bar{b})_{\bf 8}[…
In this paper we revisited phenomenological potentials. We studied S-wave heavy quarkonium spectra by two potential models. The first one is power potential and the second one is logarithmic potential. We calculated spin averaged masses, hyperfine splittings, decay constants, leptonic decay widhts, two-photon and two-gluon decay widths and some allowed M1 transitions. We studied ground and 4 radially excited S-wave charmonium and bottomonium states via solving nonrelativistic Schrödinger equation. Although the potentials were studied in this paper is not directly QCD motivated potential, obtai…
We compute the third-order corrections to the heavy quarkonium spectrum and production/annihilation rates due to the leading renormalization group running of the static potential. The previously known complete ${\cal O}(m_qα_s^5)$ result for the heavy quarkonium ground state energy is extended to the exited states. After including the ${\cal O}(α_s^3)$ corrections the perturbative results are in surprisingly good agreement with the experimental data on the masses of the excited $Υ$ resonances and the leptonic width of the $Υ(1S)$ meson. The impact of the corrections on the $Υ$ sum rules and to…
Recent results from proton(deuteron)-nucleus collisions at RHIC and LHC energies have shown an unexpected suppression of excited quarkonium states as compared to their ground states. In particular, stronger suppression of the $ψ(2S)$ relative to the $J/ψ$ has been detected. Similar observations were made at lower energies and were easily explained by nuclear absorption. At higher energies, a similar explanation would violate the Heisenberg principle, since the calculations based on the uncertainty principle lead to a charmonium formation time expected to be larger than the nuclear radius, whic…
We study the diffractive photo- and leptoproductions of $J / ψ$ and $ψ'$ on the proton, and examine the validity of the small-size color dipole approximation to the production of radially excited heavy quarkonium. The dipole model predicts a small ratio of $ψ'$ to $J / ψ$ photoproduction cross sections, which does not agree with experimental data. We show that this discrepancy originates from a large transverse size of $ψ'$ which makes the convergence of the transverse size expansion questionable, and the calculation without the dipole approximation turns out to be consistent with the data. Pr…
Main theoretical uncertainties in estimating the indirect production of $(b\bar{c})$-quarkonium ($B^-_c$ meson and its excited states) via top quark decays, $t\to (b\bar{c})+c+W^{+}$, are studied within the non-relativistic QCD framework. It is found that the dimensionless reduced decay width for a particular $(b\bar{c})$-quarkonium state, $\barΓ_{n}=Γ_{n} /Γ_{t\to W^{+}+b}$, is very sensitive to the $c$-quark mass, while the uncertainties from the $b$-quark and $t$-quark masses are small, where $n$ stands for the eight $(b\bar{c})$-quarkonium states up to ${\cal O}(v^4)$: $|(b\bar{c})(^1S_0)_…
We conjecture that a 125 GeV resonance $ζ^0$ with $J^{PC}=0^{-+}$ composed of a quark-antiquark state may have been observed at the LHC. The decay modes of this pseudoscalar particle are determined using the non-relativistic quark model. The leading order partial decay widths for the decays of the pseudoscalar quarkonium resonance $ζ^0\rightarrow γγ$ and $ζ^0\rightarrow gg$ are compared to the standard model Higgs particle decays $H^0\rightarrow γγ$ and $H^0\rightarrow gg$. An experimental analysis at the LHC of the observed production cross sections for the $ζ^0$ and the Higgs particle could …
Partial decay widths and branching fractions are calculated for the exclusive decays of the Standard Model Higgs boson into a pair of vector quarkonium states, $ H\to J/ψJ/ψ, H\to ΥΥ, H\to J/ψϕ, H\to J/ψΥ$, with relativistic corrections due to quark motion in mesons taken into account.
At the large transverse momentum region, the production of heavy-heavy bound-states such as charmonium, bottomonium, and $\bar bc$ mesons in high energy $e^+e^-$ and hadronic collisions is dominated by parton fragmentation. We calculate the heavy quark fragmentation functions into the D-wave quarkonium and $\bar bc$ mesons to leading order in the strong coupling constant and in the non-relativistic expansion. In the $\bar b c$ meson case, one set of its D-wave states is expected to lie below the open flavor threshold. The total fragmentation probability for a $\bar b$ antiquark to split into t…
Two-photon and two-gluon annihilation rates of P-wave scalar charmonium and bottomonium up to third radial excited states are estimated in the relativistic Salpeter method. We solved the full Salpeter equation with a well defined relativistic wave function and calculated the transition amplitude using the Mandelstam formalism. Our model dependent estimates for the decay widths: $Γ(χ_{c0} \to 2γ)=3.78$ keV, $Γ(χ'_{c0} \to 2γ)=3.51$ keV, $Γ(χ_{b0} \to 2γ)=48.8$ eV and $Γ(χ'_{b0} \to 2γ)=50.3$ eV. We also give estimates of total widths by the two-gluon decay rates: $Γ_{tot}(χ_{c0})=10.3$ MeV, $Γ_…
We improve the theoretical predictions for the decays of the Higgs boson to an $S$-wave vector quarkonium plus a photon by calculating the relativistic correction of order $v^2$, where $v$ is the heavy-quark velocity in the quarkonium rest frame. Our numerical results are given for the $J/ψ$ and $Υ(nS)$ channels, with $n=1,2,3$. The numerical results include a previously calculated correction of order $α_s$ and summations, to all orders in $α_s$, of leading logarithms of $m_H^2/m_Q^2$, where $m_H$ is the Higgs-boson mass and $m_Q$ is the heavy-quark mass. These QCD corrections apply to the con…
Recently it has been put forward that linearly polarized gluons inside unpolarized protons affect the transverse momentum distribution of final state particles in hadronic collisions. They lead to a characteristic modulation of the differential cross section in Higgs production and to azimuthal asymmetries in, for instance, heavy quark pair production. Here we study the effect on charmonium and bottomonium production in hadronic collisions, such as at LHCb and at the proposed fixed target experiment AFTER at LHC. We focus mainly on the scalar and pseudoscalar quarkonia, eta_c, chi_{c0}, eta_b,…
We analyze the behavior of Higgs to diphoton rate and Higgs gluon-gluon production cross section in minimal extensions of the Standard Model comprising new colored vector-like fermions that do not mix with the ordinary ones. We compare these information with constraints coming from electroweak precision measurements. We compute pair production cross sections for the lightest fermion and discuss the LHC bounds. Finally, we study the phenomenology of possible quarkonium states composed by these new colored fermions.
We extend the non-relativistic QCD (NRQCD) prediction for the production of heavy quarkonium with low transverse momentum in hadronic collisions by taking into account effects from all order soft gluon resummation. Following the Collins-Soper-Sterman formalism, we resum the most singular terms in the partonic subprocesses. The theoretical predictions of $J/ψ$ and $Υ$ productions are compared to the experimental data from the fixed target experiments (E866) and the collider experiments (RHIC, Tevatron, LHC). The associated non-perturbative Sudakov form factor for the gluon distributions is foun…
The exclusive decays of the Higgs boson to $B_c B_c$ and $B_c^\ast B_c^\ast$ pairs are studied. The hard parts of the decay amplitudes are estimated within the perturbative Standard Model up to one-loop corrections. The soft fusion of heavy quarks to the quarkonium is described in framework of the relativistic quark model.
We consider the recently suggested model for some resonances near the open charm threshold as bound states of charmonium inside excited light mesons. It is argued in the soft-wall holographic model of QCD that such states of heavy quarkonium necessarily exist at sufficiently large spin of the light meson. The bound state is provided by the dilaton exchange through the 5D bulk. We also argue that the decay of such bound systems into mesons with open heavy flavors due to splitting of the heavy quarkonium can be treated as semiclassical tunneling and is suppressed. This behavior is in agreement w…
We use QCD Laplace sum-rules to study meson-hybrid mixing in vector ($1^{--}$) heavy quarkonium. We compute the QCD cross-correlator between a heavy meson current and a heavy hybrid current within the operator product expansion. In addition to leading-order perturbation theory, we include four- and six-dimensional gluon condensate contributions as well as a six-dimensional quark condensate contribution. We construct several single and multi-resonance models that take known hadron masses as inputs. We investigate which resonances couple to both currents and so exhibit meson-hybrid mixing. Compa…
We consider the exclusive pseudoscalar heavy-quarkonium (eta_{b,c}) production in association with a photon at future lepton colliders where the collider energies of O(10^2) GeV are far greater than the quarkonium mass. At these energies, the logarithm of mass to collision energy becomes increasingly large hence its resummation becomes particularly important. By making use of the light-cone-distribution factorization formula, we resum the logarithms up to next-to-leading-logarithmic accuracy (NLL) that corresponds to order-alpha_s accuracy. We combine the resummed result with a known fixed-ord…
We revisit the heavy quarkonium leptonic decays $ψ(nS) \to \ell^+\ell^-$ and $Υ(nS) \to \ell^+\ell^-$ using the Bethe-Salpeter method. The emphasis is on the relativistic correction. For the $ψ(1S-5S)$ decays, the relativistic effects are $22^{+3}_{-2}\%$, $34^{+5}_{-5}\%$, $41^{+6}_{-6}\%$, $52^{+11}_{-13}\%$ and $62^{+14}_{-12}\%$, respectively. For the $Υ(1S-5S)$ decays, the relativistic effects are $14^{+1}_{-2}\%$, $23^{+0}_{-3}\%$, $20^{+8}_{-2}\%$, $21^{+6}_{-7}\%$ and $28^{+2}_{-7}\%$, respectively. Thus, the relativistic corrections are large and important in heavy quarkonium leptonic…
Linear polarization of gluons inside unpolarized hadrons affects the transverse momentum distribution of produced spin-0 particles, such as of the Higgs or (pseudo-)scalar quarkonium states at LHC. Despite the currently unknown amount of linear gluon polarization, a range of predictions can be obtained, using TMD evolution, which indicates that their effect is on the few percent level in Higgs production, but can be much larger in quarkonium production. Together with asymmetries in open charm or bottom production in electro-production at an Electron-Ion Collider, the size and sign of the linea…
We propose a novel mechanism for exclusive diffractive Higgs production $pp \to p H p $ in which the Higgs boson carries a significant fraction of the projectile proton momentum. This mechanism will provide a clear experimental signal for Higgs production due to the small background in this kinematic region. The key assumption underlying our analysis is the presence of intrinsic heavy flavor components of the proton bound state, whose existence at high light-cone momentum fraction $x$ has growing experimental and theoretical support. We also discuss the implications of this picture for exclusi…
We investigate the Mott effect for heavy quarkonia due to Debye screening of the heavy quark potential in a plasma of massless quarks and antiquarks. The influence of residual color correlation is investigated by coupling the light quark sector to a temporal gauge field driven by the Polyakov loop potential. This leads to an increase of the Mott dissociation temperatures for quarkonia states which stabilizes in particular the excited states, but has marginal effect on the ground states.
We argue for the existence of an upper bound $m_*$ on the Higgs mass at which the lowest excited state of the Higgs field ceases to be the conventional plane wave. An explicit construction of an alternative nonperturbative state is discussed. This excitation is spatially localized. The field fluctuations inside the localization region are large. The energy of the excitation is smaller than the mass of the plane wave state $m$ at $m>m_*$. An approximate value of $m_*$ is found to be $m_* \approx 4.75$ times the vacuum expectation value. This is an upper bound at the tree level.
I give a brief overview of the recent theoretical progress in the study of quarkonium production in proton-nucleus collisions in view of the recent LHC and RHIC results. A special emphasis is put on the excited states such as the psi', Upsilon(2S) and Upsilon(3S).
With the recent measurements on $η_{c}$ and $η_{c}^{\prime}$ at CLEO, Babar and Belle, and with the prospect of finding the $η_{b}$ at the Tevatron, it seems appropriate to have another look at the two-photon decay of heavy quarkonium from the standpoint of an effective Lagrangian based on local operator expansion and heavy-quark spin symmetry. In this talk, I would like to discuss a recent work on the two-photon decay rates of ground states and excited states of $η_c$ and $η_b$ using the local operator expansion approach and heavy-quark spin symmetry and taking into account the binding-energy…
We construct an effective Lagrangian for the hadronic decays of a heavy excited $s$-wave-spin-one quarkonium into its ground state. We show that reasonable fits to the measured invariant mass spectra in the $J/ψ$ and $Υ$ systems can be obtained working in the chiral limit. The mass dependence of the various terms in the Lagrangian is discussed on the basis of a quark model.
The production of $(b\bar{c})$-quarkonium ($\bar{B}_c$ meson and its excited states) or $(c\bar{b})$-quarkonium ($B_c$ meson and its excited states) via top quark $t$ or top anti-quark $\bar{t}$ decays, $t\to (b\bar{c})+c+W^+$ or $\bar{t}\to (c\bar{b})+\bar{c}+W^-$, respectively is studied within the framework of NRQCD. In addition to the production of the two color-singlet $S$-wave states $|(b\bar{c})(^1S_0)_{\bf 1}>$ or $|(c\bar{b})(^1S_0)_{\bf 1}>$ and $|(b\bar{c})(^3S_1)_{\bf 1}>$ or $|(c\bar{b})(^3S_1)_{\bf 1}>$, the production of the $P$-wave excited $(b\bar{c})$ or $(c\bar{b})$ states, …
The process e^+ e^- to t \bar t H is considered in the kinematic end point region where the Higgs energy is close to its maximal energy. In perturbative QCD, using the loop expansion, the amplitudes are plagued by Coulomb singularities that need to be resummed. We show that the QCD dynamics in this end point region is governed by nonrelativistic heavy quarkonium dynamics, and we use a nonrelativistic effective theory to compute the Higgs energy distribution at leading and next-to-leading logarithmic approximation in the nonrelativistic expansion. Updated numbers for the total cross section inc…
In a typical exclusive quarkonium production process, when the center-of-mass energy, $\sqrt{s}$, is much greater than the heavy quark mass $m$, large kinematic logarithms of $s/m^2$ will unavoidably arise at each order of perturbative expansion in the short-distance coefficients of the nonrelativistic QCD (NRQCD) factorization formalism, which may potentially harm the perturbative expansion. This symptom reflects that the hard regime in NRQCD factorization is too coarse and should be further factorized. We suggest that this regime can be further separated into "hard" and "collinear" degrees o…
The Kaluza-Klein excitations of the Higgs bosons of the universal extra dimension model are extremely challenging to detect. We discuss the production and possible detection mechanisms of such excited scalars at the LHC. The dominant production mechanism of such scalars is from the decay of the excited third generation quarks. In particular, the charged Higgs boson has a large production cross-section over most of the parameter space. We highlight how one may detect these excited scalars. We also comment on the production and detection of excited neutral scalars.
The issue of chiral extrapolations in heavy quarkonium systems is discussed. We show that the light quark mass dependence of the properties of heavy quarkonia is not always suppressed. For quarkonia close to an open flavor threshold, even a nonanalytic chiral extrapolation is needed. Both these nontrivial facts are demonstrated to appear in the decay widths of the hindered M1 transitions between the first radially excited and ground state P-wave charmonia. The results at a pion mass of about 500 MeV could deviate from the value at the physical pion mass by a factor of two. Our findings show th…
In this work we evaluate the masses of the $|(b\bar{s})[n]\rangle$ or $|(\bar{b}s)[n]\rangle$ quarkonium ($\bar{B}^{0}_{s}$ or ${B}^{0}_{s}$ meson) under the B.T. potential, and the values of the Schr${\rm \ddot{o}}$dinger radial wave function at the origin of the $|(b\bar{s})[n]\rangle$ or $|(\bar{b}s)[n]\rangle$ quarkonium within the five potential models. Then we investigate a systematic study on the production of the $|(b\bar{s})[n]\rangle$ or $|(\bar{b}s)[n]\rangle$ quarkonium via top quark or antitop quark decays in the color-singlet QCD factorization formula (CSQCDFF), i.e., the two $S$…
Mass spectra of quarkonium systems can be described by different phenomenological potentials. In the present work, the {\color{black}resonance} states of heavy quarkonium like ($c\bar{c}$ and $b\bar{b}$) are considered as the rovibrational states. We study a parameterized rovibrational model derived from the empirical solution of the nonrelativistic Schrödinger equation with Morse potential, the corrections are composed of colour hyperfine interaction and spin-orbit interaction of mesons. We {\color{black}obtain} the high excited state mass spectra of charmonium and bottomonium comparing the r…
In the unified subquark model of all fundamental particles and forces, the mass of the Higgs boson in the standard model of electroweak interactions ($m_H$) is predicted to be about $2\sqrt{6}m_W/3$ (where $m_W$ is the mass of the charged weak boson, $W$), which agrees well with the experimental values of about 125 GeV recently found by the ATLAS and CMS Collaborations at the LHC. It seems to indicate that the Higgs boson is a composite of the iso-doublet spinor subquark-antisubquark pairs well described by the unified subquark model with either one of subquark masses vanishing or being very s…
We show that the decay rates of the Higgs boson to a pseudoscalar quarkonium and a pair of leptons, $h\to P\ell^+\ell^-$ ($P\in\{η_c,η_b\}$), can be substantially enhanced in a scenario with two Higgs doublets with a softly broken $\mathbb{Z}_2$ symmetry (2HDM) when the CP-odd Higgs A is light, i.e. $m_A\lesssim m_h$. Depending on the type of 2HDM the enhancement of $\mathcal{B}(h\to η_{c,b}τ^+τ^-)$ with respect to its Standard Model value can be an order of magnitude larger, i.e. $\mathcal{O}(10^{-6}\div10^{-5})$. The decays $h\to P\ell^+\ell^-$ could therefore provide an efficient channel to…
Based on the two Higgs doublet model, we study the effect of Higgs-boson exchange on the (super)heavy quarkonium \bar QQ, which induces a strong attractive force between a (super)heavy quark Q and an antiquark \bar Q. An interesting application is the decay of (super)heavy quarkonia \bar QQ into a Higgs boson associated with gauge bosons. The criterion for making the \bar QQ bound state is studied. We also show that non-perturbative effects due to gluonic field fluctuations are rather small in such a heavy quark sector. Possible enhancement for productions and decays of \bar QQ bound states ma…
Heavy quarkonium decays can be used to search for New Physics beyond the Standard Model. In particular, a light Higgs boson could induce a slight (but observable) lepton universality breaking in Upsilon decays. In fact, current experimental data from CLEO presented in this Conference seem to point out to this direction within experimental accuracy. Moreover, LEP constraints on a light Higgs mass can be evaded by different models (like MSSM with a CPV Higgs sector) as shown in this Conference. We also consider spectroscopic consequences stemming from a possible mixing between Higgs and bottomon…
We investigate the Mott effect for heavy quarkonia due to Debye screening of the heavy quark potential in a plasma of massless quarks and antiquarks. The influence of residual color correlation is investigated by coupling the light quark sector to a temporal gauge field driven by the Polyakov loop potential. This leads to an increase of the Mott dissociation temperatures for quarkonia states which stabilizes in particular the excited states, but has marginal effect on the ground states. The temperature dependence of binding energies suggests that the dissciation of the charmonium (bottomonium)…
