Charged Resonance Research Articles

Higher-order geodesic deviation for charged particles and resonance induced by gravitational waves

We generalize the higher-order geodesic deviation for the structure-less test particles to the higher-order geodesic deviation equations of the charged particles [R. Kerner, J. W. van Holten and R. Colistete Jr., Class. Quantum Grav. 18 (2001) 4725]. By solving these equations for charged particles moving in a constant magnetic field in the spacetime of a gravitational wave, we show for both cases when the gravitational wave is parallel and perpendicular to the constant magnetic field, a magnetic resonance appears at [Formula: see text]. This feature might be useful to detect the gravitational wave with high frequencies.

Two charmoniumlike charged axial resonances near 3885 MeV

It is argued that the charged $Z^+_c(3885)$ resonance, treated as a `molecular' state of charmed $D$ and $D^*$ mesons, is likely to consist of two peaks unequally coupled to the $D^{*+} \bar D^0$ and $D^+ \bar D^{*0}$ channels. The peaks should be split in mass by at least approximately 1.5 MeV. This behavior arises from an enhancement of the effect of isospin violation in the masses of the $D$ and $D^*$ mesons due to apparent suppression of forces between the mesons depending on the spins of the heavy as well as of the light quarks. The suggested double-peak structure can be studied either by direct shape measurement in the channels with heavy mesons, or by isospin-violating transitions from $Z_c^\pm(3885)$ to the states of charmonium plus a light meson.

Search for a massive resonance decaying into a Higgs boson and a W or Z boson in hadronic final states in proton-proton collisions at s = 8 $$ \sqrt{s}=8 $$ TeV

A search for a massive resonance decaying into a standard-model-like Higgs boson (H) and a W or Z boson is reported. The analysis is performed on a data sample corresponding to an integrated luminosity of 19.7 inverse femtobarns, collected in proton-proton collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC. Signal events, in which the decay products of Higgs, W, or Z bosons at high Lorentz boost are contained within single reconstructed jets, are identified using jet substructure techniques, including the tagging of b hadrons. This is the first search for heavy resonances decaying into HW or HZ resulting in an all-jet final state, as well as the first application of jet substructure techniques to identify H to WW* to 4q decays at high Lorentz boost. No significant signal is observed and limits are set at 95% confidence level on the production cross section of W' and Z' in a model with mass-degenerate charged and neutral spin-1 resonances. Resonance masses are excluded for W' in the interval [1.0, 1.6] TeV, for Z' in the intervals [1.0, 1.1] and [1.3, 1.5] TeV, and for mass-degenerate W' and Z' in the interval [1.0, 1.7] TeV.

Combination of searches for WW, WZ, and ZZ resonances in pp collisions at s=8 TeV with the ATLAS detector

The ATLAS experiment at the CERN Large Hadron Collider has performed searches for new, heavy bosons decaying to $WW$, $WZ$ and $ZZ$ final states in multiple decay channels using 20.3 fb$^{-1}$ of $pp$ collision data at $\sqrt{s} = 8$ TeV. In the current study, the results of these searches are combined to provide a more stringent test of models predicting heavy resonances with couplings to vector bosons. Direct searches for a charged diboson resonance decaying to WZ in the $\ell\nu\ell'\ell'$ ($\ell = \mu, e$) , $\ell\ell q \bar{q}$, $\ell \nu q \bar{q}$ and fully hadronic final states are combined and upper limits on the rate of production times branching ratio to the $WZ$ bosons are compared with predictions of an extended gauge model with a heavy $W'$ boson. In addition, direct searches for a neutral diboson resonance decaying to $WW$ and $ZZ$ in the $\ell \ell q \bar{q}$, $\ell \nu q \bar{q}$, and fully hadronic final states are combined and upper limits on the rate of production times branching ratio to the $WW$ and $ZZ$ bosons are compared with predictions for a heavy, spin-2 graviton in an extended Randall--Sundrum model where the Standard Model fields are allowed to propagate in the bulk of the extra dimension.

Search for Resonances Decaying to Top and Bottom Quarks with the CDF Experiment

We report on a search for charged massive resonances decaying to top (t) and bottom (b) quarks in the full data set of proton-antiproton collisions at a center-of-mass energy of √[s]=1.96 TeV collected by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.5 fb(-1). No significant excess above the standard model background prediction is observed. We set 95% Bayesian credibility mass-dependent upper limits on the heavy charged-particle production cross section times branching ratio to tb. Using a standard model extension with a W'→tb and left-right-symmetric couplings as a benchmark model, we constrain the W' mass and couplings in the 300-900 GeV/c(2) range. The limits presented here are the most stringent for a charged resonance with mass in the range 300-600 GeV/c(2) decaying to top and bottom quarks.

$$Z_c(4200)^+$$ Z c ( 4200 ) + decay width as a charmonium-like tetraquark state

To identify the nature of the newly observed charged resonance Zc(4200), we study its hadronic decays Zc(4200) -> J/psi pi, Zc(4200) -> eta_c rho and Zc(4200) -> D bar D* as a charmonium-like tetraquark state. In the framework of the QCD sum rules, we calculate the three-point functions and extract the coupling constants and decay widths for these interaction vertices. Including all these channels, the full decay width of the Zc(4200) state is consistent with the experimental value reported by the Belle Collaboration, supporting the tetraquark interpretation of this state.

Future tests of Higgs compositeness: direct vs indirect

We estimate the reach of the 14 TeV LHC and future hadronic and leptonic colliders in the parameter space of the minimal composite Higgs model, outlining the complementarity of direct resonance searches and indirect information from the measurements of the Higgs boson couplings. The reach on electroweak charged spin-one resonances, taken here as representative direct signatures, is obtained from the current 8 TeV LHC limits by an extrapolation procedure which we outline and validate. The impact of electroweak precision tests, and their possible improvement at future colliders, is also quantified.

Can new heavy gauge bosons be observed in ultra-high energy cosmic neutrino events?

A wide range of models beyond the Standard Model predict charged and neutral resonances, generically called $W'$- and $Z'$-bosons, respectively. In this paper we study the impact of such resonances on the deep inelastic scattering of ultra-high energy neutrinos as well as on the resonant charged current $\bar\nu_e e^-$ scattering (Glashow resonance). We find that the effects of such resonances can not be observed with the Pierre Auger Observatory or any foreseeable upgrade of it.

New States with Heavy Quarks

We discuss several highly accurate theoretical predictions for masses of baryons containing the b quark which have been recently confirmed by experimental data. Proper treatment of the color-magnetic hyperfine interaction in QCD is crucial for obtaining these results. Several predictions are given for additional properties of heavy baryons. We also discuss the two charged exotic resonances Z b with quantum numbers of a ( b u ) tetraquark, very recently reported by Belle in the channel [ϒ( nS )π + , n = 1, 2, 3]. Among possible implications are deeply bound I = 0 counterparts of the Z b -s and existence of a Σ b + Σ b − dibaryon, a beauteron .

Protonation-Induced Chromism of Pyridylethynyl-Appended [core+exo]-Type Au8 Clusters. Resonance-Coupled Electronic Perturbation through π-Conjugated Group

A series of [core+exo]-type Au8 clusters bearing two alkynyl ligands on the exo gold atoms ([Au8(dppp)4(C≡CR)2](2+), 2-6) were synthesized by the reaction of [Au8(dppp)4](2+) (1) with alkynyl anions. Although the C≡C moieties directly attached to the Au8 units did not affect the optical properties arising from intracluster transitions, the pyridylethynyl-bearing clusters (4-6) exhibited reversible visible absorption and photoluminescence responses to protonation/deprotonation events of the terminal pyridyl moieties. The chromism behaviors and proton-binding constants of these clusters were highly dependent on the relative position of the pyridine nitrogen atom, such that the 2-pyridyl (4) and 4-pyridyl (6) isomers showed more pronounced responses than the 3-pyridyl isomer (5). These results suggest that the resonance-coupled movement of the positive charge upon protonation is involved in the optical responses, where the formation of extended charged resonance structures causes significant perturbation effects on the electronic properties of the Au8 unit and also contributes to the high binding affinities.

Tetraquarks, their masses and decays in QED2

Recent observations by Belle and BESIII of charged quarkonium-like resonances give new stimulus for theoretical investigation of exotic hadrons in general and heavy tetraquarks in particular. We use QED_2, a confining theory, as a model for the masses and decays of tetraquarks. Here we discuss the states (Q Qbar q qbar) and (Q Q qbar qbar) (and its anti-particle), where Q and q are two fermion flavors with masses M and m, so that M > m. We then discuss decay modes of these states into (Q Qqbar), (q qbar), (Q qbar), (Qbar q). It turns out that (Q Qbar q qbar) is stable, while (Q Q qbar qbar) is not.

The doubly heavies: $ \overline{Q}Q\overline{q}q $ and $ QQ\overline{q}\overline{q} $ tetraquarks and QQq baryons

Recent discoveries by Belle and BESIII of charged exotic quarkonium-like resonances provide fresh impetus for study of heavy exotic hadrons. In the limit N c → ∞, M Q → ∞ the $ \overline{Q}Q\overline{q}{q^{\prime }} $ tetraquarks (TQ-s) are expected to be narrow and slightly below or above the $ \overline{Q}{q^{\prime }} $ and $ Q\overline{q} $ two-meson threshold. The isoscalar TQ-s manifest themselves by decay to $ \left( {\overline{Q}Q} \right) $ ππ, and the ~30 MeV heavier charged isotriplet TQ-s by decays into $ \left( {\overline{Q}Q} \right) $ π . The new data strongly suggest that the real world with N c = 3, Q = c, b and q,q ′ = u,d is qualitatively described by the above limit. We discuss the relevant theoretical estimates and suggest new signatures for TQ-s in light of the recent discoveries. We also consider “baryon-like” states $ Q{Q^{\prime }}\overline{q}{{\overline{q}}^{\prime }} $ , which if found will be direct evidence not just for near-threshold binding of two heavy mesons, but for genuine tetraquarks with novel color networks. We stress the importance of experimental search for doubly-heavy baryons in this context.

JPG=1++charged resonance in theΥ(4260)→π+π−J/ψdecay?

New BES and Belle data show a peak in the $Y(4260)$ decay into $J/\ensuremath{\psi}$ plus one charged pion. We point out that the peak might correspond to a charged resonance at about 3880 MeV predicted some time ago within a tetraquark model. The same tetraquark model predicts another peak at about 100 MeV below the observed one. We discuss the possibility of having it in present data. On the other hand we expect that if the molecular picture were the correct one, a peak corresponding to a ${D}^{*}{\overline{D}}^{*}$ state should appear at about 4020 MeV.

Exploring Drell-Yan signals from the 4D Composite Higgs Model at the LHC

We study the phenomenology of Drell-Yan processes at the Large Hadron Collider for the case of both the neutral and charged current channels within a recently proposed 4-Dimensional formulation of the Minimal Composite Higgs Model. We estimate the integrated and differential event rates at the CERN machine, assuming 14 TeV and data samples of ${\cal O}(100 {\rm{fb}}^{-1})$, as at lower energy and/or luminosity event rates are prohibitively small. We pay particular attention to the presence of multiple resonances in either channel, by showing that in certain region of parameter space some of these can be distinguishable and experimentally accessible in the invariant and/or transverse mass distribution, sampled in either the cross section, the forward-backward asymmetry or both. At the same time, we assess the indirect impact onto the line-shape of the emerging gauge boson resonances, both neutral and charged, of additional heavy fermionic states present in the spectrum of the model. Finally, we show how to exploit in the kinematic selection the fact that the extra neutral and charged gauge boson resonances in composite Higgs models are correlated in mass. Such results rely on a parton level study including a statystical error analysis.

Possible interpretation of the Zb(10610) and Zb(10650) in a chiral quark model

Motivated by the two charged bottomonium-like resonances Zb(10610) and Zb(10650) newly observed by the Belle collaboration, the possible molecular states composed of a pair of heavy mesons, , etc (in S-wave), are investigated in the framework of chiral quark models by the Gaussian expansion method. The bound states and with quantum numbers I(JPC) = 1(1+−), which are good candidates for the Zb(10610) and Zb(10650), respectively, are obtained. Another three bound states with I(JPC) = 0(1++), with I(JPC) = 1(0++), 0(2++) are predicted. These states may be observed in an open-bottom or a hidden-bottom decay channel of highly excited ϒ. When directly extending the quark model to the hidden-color channel of the multi-quark system, more deeply bound states are found. Future experimental search of those states will cast doubt on the validity of applying the chiral constituent quark model to the hidden-color channel directly.

New States with Heavy Quarks

We discuss several highly accurate theoretical predictions for masses of baryons containing the b quark which have been recently confirmed by experimental data. Several predictions are given for additional properties of heavy baryons. We also discuss the two charged exotic resonances Z b with quantum numbers of a ( b b ¯ u d ¯ ) tetraquark, very recently reported by Belle in the channel [ ϒ ( n S ) π + , n = 1 , 2 , 3 ] . Among possible implications are deeply bound I = 0 counterparts of the Z b -s and existence of a Σ b + Σ b − dibaryon, a beauteron.

Probing novel scalar and tensor interactions from (ultra)cold neutrons to the LHC

Scalar and tensor interactions were once competitors to the now well-established $V\ensuremath{-}A$ structure of the standard model weak interactions. We revisit these interactions and survey constraints from low-energy probes (neutron, nuclear, and pion decays) as well as collider searches. Currently, the most stringent limit on scalar and tensor interactions arise from ${0}^{+}\ensuremath{\rightarrow}{0}^{+}$ nuclear decays and the radiative pion decay $\ensuremath{\pi}\ensuremath{\rightarrow}e\ensuremath{\nu}\ensuremath{\gamma}$, respectively. For the future, we find that upcoming neutron beta decay and LHC measurements will compete in setting the most stringent bounds. For neutron beta decay, we demonstrate the importance of lattice computations of the neutron-to-proton matrix elements to setting limits on these interactions, and provide the first lattice estimate of the scalar charge and a new average of existing results for the tensor charge. Data taken at the LHC is currently probing these interactions at the ${10}^{\ensuremath{-}2}$ level (relative to the standard weak interactions), with the potential to reach the $\ensuremath{\lesssim}{10}^{\ensuremath{-}3}$ level. We show that, with some theoretical assumptions, the discovery of a charged spin-0 resonance decaying to an electron and missing energy implies a lower limit on the strength of scalar interactions probed at low energy.

Discovery in Drell-Yan processes at the LHC

We study the Drell-Yan process mediated by a new bosonic resonance at the LHC. The bosons of spin-0, 1, and 2 with the most general leading-order couplings to standard model fermions and gluons are considered, which provides a model-independent formulation for future exploration of the resonance properties, such as its spin, mass and couplings. In the case of neutral resonances, we demonstrate how the shapes of the kinematical distributions change as one varies the chiral couplings of the quarks and leptons, and show how to analyze the couplings by making use of the forward-backward asymmetry. In the case of charged resonances, we propose a novel technique to effectively reconstruct the angular distribution in the center-of-mass frame, to a large extent avoiding the two-fold ambiguity due to the missing neutrino. Similar to the case of a neutral resonance, the spin information of the resonance can be extracted unambiguously, and chiral couplings and the asymmetries can be explored in a statistical manner. With the current LHC data, we present bounds on the mass and cross section times branching fraction of the new resonance and estimate the future reach.

Charge asymmetry ratio as a probe of quark flavour couplings of resonant particles at the LHC

We show how a precise knowledge of parton distribution functions, in particular those of the u and d quarks, can be used to constrain a certain class of New Physics models in which new heavy charged resonances couple to quarks and leptons. We illustrate the method by considering a left–right symmetric model with a W′ from a SU(2) R gauge sector produced in quark–antiquark annihilation and decaying into a charged lepton and a heavy Majorana neutrino. We discuss a number of quark and lepton mixing scenarios, and simulate both signals and backgrounds in order to determine the size of the expected charge asymmetry. We show that various quark–W′ mixing scenarios can indeed be constrained by charge asymmetry measurements at the LHC, particularly at $\sqrt{s}= 14$ TeV.

Charged charmonium molecules

We make use of a self-consistent quark-model based study of four-quark charmonium-like states to interpret recent charmonium experimental data. We conclude that there exists a ${D}^{*}{\overline{D}}^{*}$ meson-meson molecule with quantum numbers $({I}^{G}){J}^{PC}=({1}^{\ensuremath{-}}){2}^{++}$. Our study confirms the presence of charged charmonium-like resonances on the excited charmonium spectrum. We find support from recent experimental data by the Belle Collaboration [R. Mizuk et al. (Belle Collaboration), Phys. Rev. D 78, 072004 (2008)]. Confirmation of the experimental data by the Belle Collaboration and the determination of the quantum numbers of the new structures would help in discriminating among different theoretical models and would give further support to the theoretical analysis of T. Fern\'andez-Caram\'es, A. Valcarce, and J. Vijande [Phys. Rev. Lett. 103, 222001 (2009)].