The Born cross section and dressed cross section of $e^+e^-$ to $b\bar{b}$ and the total hadronic cross section in $e^+e^-$ annihilation in the bottomonium energy region are calculated based on the Rb values measured by the BaBar and Belle experiments. The data are used to calculate the vacuum polarization factors in the bottomonium energy region, and to determine the resonant parameters of the vector bottomonium(-like) states, the Y(10750), Upsilon(5S), and Upsilon(6S).
We perform the first global and unitary analysis of $e^+e^-\to b\bar{b}$ cross sections. We analyze exclusive cross sections in the $B\bar{B}$, $B^* \bar{B}(+c.c.)$, $B^*\bar{B}^*$, $B_s^*\bar{B}_s^*$, $Υ(nS)π^+π^-$ and $h_b(nP)π^+π^-$ channels as well as the total inclusive cross section for $b\bar{b}$ production. Pole positions and residues are determined for four vector states, which we associate with the $Υ(4S)$, $Υ(10750)$, $Υ(5S)$ (or $Υ(10860)$), and $Υ(6S)$ (or $Υ(11020)$). We find strong evidence for the new $Υ(10750)$ recently claimed by Belle, although with parameters not well const…
The $1^1D_2 (c\bar c)$ state is the ground state of spin-singlet D-wave charmonia. Although it has not been found yet, the experimental data accumulate rapidly. This charmonium attracts more and more attention, especially when the BaBar Collaboration finds that the X(3872) particle has negative parity. In this paper we calculate the double-gamma and double-gluon annihilation processes of $^1D_2$ charmonia and bottomonia by using the instantaneous Bethe-Salpeter method. We find the relativistic corrections make the decay widths of $1^1D_2 (c\bar c)$ 2$\sim$5 times smaller than the non-relativis…
The production cross sections of $J/ψ~η_b$, $Υ\;η_c$ pairs in a single boson $e^+e^-$ annihilation have been studied in a wide range of energies, which will be achieved at future $e^+e^-$ colliders. The main color singlet contributions to the production processes are taken into account, including the one loop QCD contribution.
Two-photon annihilation rates of $2^+$ tensor charmonium and bottomonium up to third radial excited states are estimated in the relativistic Salpeter method. Full Salpeter equation for $2^+$ tensor state is solved with a well defined relativistic wave function and we calculated the annihilation amplitude using the Mandelstam formalism. Our estimates of the decay widths are: $Γ(χ_{c2} \to 2γ)=501$ eV, $Γ(χ'_{c2} \to 2γ)=534$ eV, $Γ(χ_{b2} \to 2γ)=7.4$ eV and $Γ(χ'_{b2} \to 2γ)=7.7$ eV. We also give total decay widths of the lowest states estimated by the two-gluon decay rates, and the results a…
We report on a recent computation of the transitions of exotic bottomonium to standard bottomonium and light quark hadrons. We work under the assumption that the $Υ(10753)$ and $Υ(11020)$ can be described as the lowest laying and first excitation $1^{--}$ hybrid bottomonium states, respectively. The computation has two distinct parts: the heavy quark transition matrix elements, which are obtained in a nonrelativistic EFT incorporating the heavy quark, multipole and adiabatic expansions; and the hadronization of the gluonic operators into the light-meson final states. The single mesons producti…
Pion exchange in S-wave between hadrons that are themselves in a relative S-wave is shown to shift energies by hundreds of MeV, leading to deeply bound quasi-molecular states. In the case of charmed mesons $D^*,D_1$ a spectroscopy arises consistent with enigmatic charmonium states observed above 4 GeV in $e^+e^-$ annihilation. A possible explanation of $Y(4260)\to ψππ$ and $Y(4360) \to ψ'ππ$ is found. We give results for all isospin and charge-conjugation combinations, and comment on flavor exotic doubly charmed states and bottomonium analogs. A search in $D\bar{D}3π$ is recommended to test th…
We revisit the bottomonium spectrum motivated by the recently exciting experimental progress in the observation of new bottomonium states, both conventional and unconventional. Our framework is a nonrelativistic constituent quark model which has been applied to a wide range of hadronic observables from the light to the heavy quark sector and thus the model parameters are completely constrained. Beyond the spectrum, we provide a large number of electromagnetic, strong and hadronic decays in order to discuss the quark content of the bottomonium states and give more insights about the better way …
We calculate the in-medium masses of the bottomonium states ($Υ(1S)$, $Υ(2S)$, $Υ(3S)$ and $Υ(4S)$) in isospin asymmetric strange hadronic matter at finite temperatures. The medium modifications of the masses arise due to the interaction of these heavy quarkonium states with the gluon condensates of QCD. The gluon condensates in the hot hadronic matter are computed from the medium modification of a scalar dilaton field within a chiral SU(3) model, introduced in the hadronic model to incorporate the broken scale invariance of QCD. There is seen to be drop in the masses of the bottomonium states…
In this work, we investigate the $Υ(10753)\toΥ(nS)π^+π^-$ ($n=1,2,3$) processes by considering the hadronic loop mechanism, where $Υ(10753)$ is assigned to a conventional bottomonium in the $4S$-$3D$ mixing scheme. Our results of the concerned processes own considerable branching ratios, which can reach up to the order of magnitude of $10^{-4}-10^{-3}$. We should indicate that the measured $Γ_{e^+e^-}\times\mathcal{B}[Υ(10753)\toΥ(nS)π^+π^-]$ values given by Belle can be reproduced well. This fact supports the former bottomonium assignment to the $Υ(10753)$ in the $4S$-$3D$ mixing scheme. Obvi…
In this work, we extended our statistical model with charmed and bottomed hadrons, and fit the quark creational probabilities for the heavy quarks, using low energy inclusive charmonium and bottomonium data. With the finalized fit for all the relevant types of quarks (up, down, strange, charm, bottom) at the energy range from a few GeV up to a few tens of GeV's, the model is now considered complete. Some examples are also given for proton-proton, pion-proton, and proton-antiproton collisions with charmonium, bottomonium, and open charm hadrons in the final state.
We have applied Pade approximants to perturbative QCD calculations of event shape observables in e+e- --> hadrons. We used the exact O(alpha_s^2) prediction and the [0/1] Pade approximant to estimate the O(alpha_s^3) term for 15 observables, and in each case determined alpha_s(M_Z^2) from comparison with hadronic Z^0 decay data from the SLD experiment. We found the scatter among the alpha_s(M_Z^2) values to be significantly reduced compared with the standard O(alpha_s^2) determination, implying that the Pade method provides at least a partial approximation of higher-order perturbative contribu…
We present evidence for small oscillations we observe in electron-positron and proton-antiproton annihilation data, with a periodicity of 76+-2 MeV, independent of the beam energy. We discuss some possible scenarios to explain the phenomenon.
We have applied so-called `optimised' perturbation theory to resolve the renormalisation-scale (mu) ambiguity of exact O(alpha_s^2) QCD calculations of event shape observables in e+e- --> hadrons. We fitted the optimised predictions for 15 observables to hadronic Z0 decay data from the SLD experiment to determine alpha_s(M_Z^2). Comparing with results using the physical scale mu = M_Z we found no reduction in the scatter among alpha_s(M_Z^2) values from the 15 observables, implying that the O(alpha_s^2) predictions with optimised scales are numerically no closer to the exact all-orders results…
We present the first determination of the strong coupling constant from a fit of next-to-next-to-leading order QCD predictions to event-shape variables, measured in $e^+e^-$ annihilations at LEP. The data have been collected by the ALEPH detector at centre-of-mass energies between 91 and 206 GeV. Compared to results of next-to-leading order fits we observe that the central fit values are lower by about 10%, with considerably reduced scatter among the results obtained with different event-shape variables. The dominant systematic uncertainty from renormalization scale variations is reduced by a …
We review the results on the XYZ states from the Belle experiment, including the measurement of inclusive hadronic cross sections and exclusive cross sections in e+e- annihilation and the Z_b states in the bottomonium energy region; and the study of the Y states and the Z_c states in charmonium energy region.
Events with tagged photons in the process of electron-positron annihilation into hadrons are considered. The initial state radiation is suggested to scan the hadronic cross section with the energy. QED radiative corrections are taken into account. The results for the total and exclusive cross sections are given in an analytic form. Some numerical estimates are presented.
We investigate the production and absorption of $Z_b (10610)$ and $Z_b ^{\prime}(10650)$ states in a hadronic medium, via the processes $\bar{B}^{(*)} B^{(*)} \rightarrow πZ_b ^{(\prime)} $ and the corresponding inverses reactions. We use effective field Lagrangians based on an $SU(4)$-extension of the hidden gauge formalism to account for the couplings between light and heavy mesons, and a phenomenological Lagrangian involving the $ B^{\ast} B^{(\ast)} Z_b ^{(\prime)}$ vertices. The absorption cross sections are found to be much larger than the production ones.
The production of four hadronic jets in e+e- collisions above the Z pole is dominated by the QCD e+e- --> qqqq,qqgg processes and, for sufficiently high energy, the electroweak e+e- --> W+W- --> qqqq process. However there is another mechanism for producing four jets, e+e- --> Z gg --> qqgg, which can be regarded as a `hadronic return' to the Z pole. We investigate this new process in detail
The two-body mesonic $B$ decays induced only via a single $W$-exchange or annihilation quark diagram, such as $B^-_u\rightarrow D^{(*)-}_sK^{(*)0}$ and $\bar{B}^0_d\rightarrow D^{(*)+}_sK^{(*)-}$, are analyzed in the factorization approximation. We estimate the branching ratios for those transitions into two pseudoscalar mesons, and find them to be negligibly small. The significant effect of final-state rescattering is illustrated by taking $B^-_u\rightarrow D^-\bar{K}^0$ for example.
Hadronic annihilation rate of $1^{+-}$ heavy quarkonium is given to next-to-leading order in $α_s$ and leading order in $v^2$ using a recently developed factorization formalism which is based on NRQCD. The result includes both the annihilation of P-wave color-singlet $Q\bar{Q}$ component, and the annihilation of S-wave color-octet $Q\bar{Q}$ component of the quarkonium. The notorious infrared divergences due to soft gluons, i.e., the Logarithms associated with the binding energy, encountered in previous perturbative calculations of $1^{+-}$ quarkonium decays are found to be explicitly cancelle…
In the framework of a newly developed factorization formalism which is based on NRQCD, explicit cancellations are shown for the infrared divergences that appeared in the previously calculated hadronic annihilation decay rates of P-wave and D-wave heavy quarkonia. We extend them to a more general case that to leading order in $v^2$ and next-to-leading order in $α_s$, the infrared divergences in the annihilation amplitudes of color-singlet $Q\bar{Q}(^{2S+1}L_J)$ pair can be removed by including the contributions of color-octet operators $Q\bar{Q}(^{2S+1}(L-1)_{J'})$, $Q\bar{Q}(^{2S+1}(L-3)_{J''}…
We provide complete analytic expressions for the inclusive prompt photon production cross section in hadronic final states of $e^+e^-$ annihilation reactions through one-loop order in quantum chromodynamics perturbation theory. Computed explicitly are direct photon production through first order in the electromagnetic strength $α_{em}$ and the quark-to-photon and gluon-to-photon fragmentation contributions through first order in the strong coupling $α_s$. The full angular dependence of the cross sections is displayed, separated into transverse $(1 +\cos ^2θ_γ)$ and longitudinal $(\sin ^2θ_γ)$ …
We provide complete analytic expressions for the isolated prompt photon production cross section in $e^+e^-$ annihilation reactions through one-loop order in quantum chromodynamics (QCD) perturbation theory. Functional dependences on the isolation cone size $δ$ and isolation energy parameter $ε$ are derived. The energy dependence as well as the full angular dependence of the cross section on $θ_γ$ are displayed, where $θ_γ$ specifies the direction of the photon with respect to the $e^+e^-$ collision axis. We point out that conventional perturbative QCD factorization breaks down for isolated ph…
Electron-positron annihilation into hadrons plus an energetic photon from initial state radiation allows the hadronic cross-section to be measured over a wide range of energies. The full next-to-leading order QED corrections for the cross-section for e^+ e^- annihilation into a real tagged photon and a virtual photon converting into hadrons are calculated where the tagged photon is radiated off the initial electron or positron. This includes virtual and soft photon corrections to the process e^+ e^- \to γ+γ^* and the emission of two real hard photons: e^+ e^- \to γ+ γ+ γ^*. A Monte Carlo gener…
The evaluation of the hadronic contribution to the muon magnetic anomaly $a_μ$ is revisited, taking advantage of new experimental data on $e^+e^-$ annihilation into hadrons: SND and CMD-2 for the $π^+π^-$ channel, and \babar for multihadron final states. Discrepancies are observed between KLOE and CMD-2/SND data, preventing one from averaging all the $e^+e^-$ results. The long-standing disagreement between spectral functions obtained from $τ$ decays and $e^+e^-$ annihilation is still present, and not accounted by isospin-breaking corrections, for which new estimates have been presented. The up…
GeV-scale dark matter is an increasingly attractive target for direct detection, indirect detection, and collider searches. Its annihilation into hadronic final states produces a challenging zoo of light hadronic resonances. We update Herwig7 to study the photon and positron spectra from annihilation through a vector mediator. It covers dark matter masses between 250 MeV and 5 GeV and includes an error estimate.
In this work we evaluate the cross section of the process $e^+e^-\to J/ψη_c$ at energy $\sqrt{s}\approx 10.6$ GeV in the Bethe-Salpeter formalism. To simplify our calculation, the heavy quark limit is employed. Without taking the beyond-leading-order contribution(s) into account, the cross section calculated in this scenario is comparable with the experimental data. We also present our prediction for the cross section of double bottomonium production $e^+e^-\to Υ(1S)η_b$ for the energy range of $\sqrt{s}\approx (25 \hbox{-} 30)$ GeV which may be experimentally tested, even though there is no f…
Both charm and bottom quarks form nonrelativistic bound states analogous to positronium. The J/psi and psi(2S) charmonium states and the first three Upsilon(nS) bottomonium states, all spin-triplet S-wave quarkonium states below open-heavy-flavor thresholds, have relatively large branching ratios to e- e+ or mu- mu+ pairs. In hadron collisions, experiments measuring lepton pairs can determine polarization by using angular correlation techniques. The polarization, in turn, can be related theoretically to the production mechanism for the bound state. This review summarizes experimental studies w…
A coherent study of $e^{+}e^{-}$ annihilation into two ($π^{+}π^{-}$,$K^{+}K^{-}$) and three ($π^{+}π^{-}π^{0},π^{+}π^{-}η$) pseudoscalar meson production is carried out within the framework of resonance chiral theory in energy region $E\lesssim 2 \, \mathrm{GeV}$. The work of {[}L. Y. Dai, J. Portolés, and O. Shekhovtsova, Phys. Rev. D 88,056001 (2013){]} is revisited with the latest experimental data and a joint analysis of two pseudoscalar meson production. Hence, we evaluate the lowest order hadronic vacuum polarization contributions of those two and three pseudoscalar processes to the ano…
Motivated by the recent observation of CP violation in the charm sector by LHCb, we study direct CP asymmetries in the standard model (SM) for the singly Cabibbo-suppressed two-body hadronic decays of charmed mesons using the topological-diagram approach. In this approach, the magnitude and the phase of topological weak annihilation amplitudes which arise mainly from final-state rescattering can be extracted from the data. Consequently, direct CP asymmetry $a_{dir}^{\rm (tree)}$ at tree level can be reliably estimated. In general, it lies in the range $10^{-4}<a_{dir}^{\rm (tree)}<10^{-3}$. Sh…
It is demonstrated how perturbative O(alpha_s^2) relativistic corrections to the non-relativistic stable heavy quark-antiquark production cross section in e^+e^- annihilation based on a Coulombic QCD potential can be systematically calculated using the concept of effective field theories. The O(alpha_s^2) corrections from the relativistic energy-momentum relation, the relativistic phase space corrections and the O(alpha_s^2) corrections involving the group theoretical factors C_F^2 and C_F T are determined explicitly. For the case of $t\bar t$ production the sum of these corrections amounts to…
We discuss the relic abundance of massive long lived colored particles with mass of the order of 1 TeV. We first examine the case where the massive colored particles have the standard color only. Next we consider the "Quirk Model" suggested by M. Luty, in which the colored particles transform under an additional non-abelian gauge group with a scale much smaller than the particles' mass. In both cases, the relic abundance is reduced via a "late" hadronic annihilation stage. In the second case the relic Quirks bind to ordinary quarks forming fractional charged objects and also anomalous heavy is…
We point out that the variance of net-baryon distribution normalized by the Skellam distribution baseline, $κ_2[B-\bar{B}]/\langle B+\bar{B}\rangle$, is sensitive to the possible modification of (anti)baryon yields due to $B\bar{B}$ annihilation in the hadronic phase. The corresponding measurements can thus place stringent limits on the magnitude of the $B\bar{B}$ annihilation and its inverse reaction. We perform Monte Carlo simulations of the hadronic phase in Pb-Pb collisions at the LHC via the recently developed subensemble sampler + UrQMD afterburner and show that the effect survives in ne…
We present a complete calculation of the electroweak O(alpha^3 alpha_s) corrections to three-jet production and related event-shape observables at electron--positron colliders. The Z-boson resonance is described within the complex-mass scheme, rendering the calculation valid both in the resonance and off-shell regions. Higher-order initial-state radiation is included in the leading-logarithmic approximation. We properly account for the corrections to the total hadronic cross section and for the experimental photon isolation criteria. To this end we implement contributions of the quark-to-photo…
The centrality dependence of the $p/π$ ratio measured by the ALICE Collaboration in 5.02 TeV Pb-Pb collisions indicates a statistically significant suppression with the increase of the charged particle multiplicity once the centrality-correlated part of the systematic uncertainty is eliminated from the data. We argue that this behavior can be attributed to baryon annihilation in the hadronic phase. By implementing the $B\bar{B} \leftrightarrow 5π$ reaction within a generalized partial chemical equilibrium framework, we estimate the annihilation freeze-out temperature at different centralities,…
The BaBar collaboration has an extensive program of studying hadronic cross sections in low-energy e+e- collisions, accessible via initial-state radiation. Our measurements allow significant improvements in the precision of the predicted value of the muon anomalous magnetic moment. These improvements are necessary for illuminating the current ~3.6 sigma difference between the predicted and the experimental values. We have published results on a number of processes with two to six hadrons in the final state. We report here the results of recent studies with final states that constitute the main…
We study the hadronic D meson decays into a pseudoscalar meson $P$ and an even-parity meson $M$, where $M$ represents a scalar meson $S$, an axial-vector meson $A$, or a tensor meson $T$. These decays are first analyzed in the flavor-diagram approach. Fits to the $SP$ modes with $S$ being a non-strange scalar meson show that neither the simple $q\bar q$ picture nor the $q^2\bar q^2$ scheme is favored by data. Current measurements on the $AP$ decays are insufficient for a meaningful analysis. Some $TP$ data are inconsistent with the others. In certain cases, the $W$-annihilation diagrams indica…
We study the $Y(4260)$ production mechanism in $e^+e^-$ annihilations in the framework of hadronic molecules and investigate the consequence of such a picture in different decay channels. In the hadronic molecule picture the $Y(4260)$ is described as a mixture state composed of a long-ranged $\bar{D}D_1(2420)+c.c.$ molecule state and a compact $c\bar{c}$ component. We show that the compositeness relation can still provide a reasonable constraint on the wavefunction renormalization parameter due to the dominance of the molecular component. Such a mechanism can be regarded as a natural consequen…
We propose an alternative evaluation of the long-distance weak annihilation (WA, also called one-photon exchange in this paper) contribution to the rare semileptonic $B^{\pm}\to (π^{\pm},K^{\pm})\ell^+\ell^-$ ($\ell=e,\,μ$) decays. This hadronic description at low energies is matched at intermediate energies to its short-distance counterpart in terms of quark and gluon degrees of freedom. Although the WA contribution does not contribute to solve the possible breaking of lepton-universality observed by LHCb in the $B^{\pm}\to K^{\pm}(μ^+μ^-/e^+e^-)$ ratio, nor provides an important hadronic con…
Using recent CLEO III results for the cross section for $e^+e^- \to {\rm hadrons}$ at seven centre-of-mass energies between 6.964 and 10.538 GeV, we derive a value for the strong coupling constant $α_s(M_Z^2)=0.110_{-0.012}^{-0.010}{}_{-0.011}^{+0.010}$ where the uncertainties are uncorrelated and correlated, respectively. Our result differs significantly from the one derived by CLEO III, as a consequence of inclusion of quark mass effects and the proper matching between the effective theories with four and five flavours. Combining this new result with an analysis based on earlier cross sectio…
We examine the effects of relic dark matter annihilations on big bang nucleosynthesis (BBN). The magnitude of these effects have scale simply with the dark matter mass and annihilation cross-section, which we derive. Estimates based on these scaling behaviors indicate that BBN severely constrains hadronic and radiative dark matter annihilation channels in the previously unconsidered dark matter mass region MeV $\lesssim m_χ \lesssim 10$ GeV. Interestingly, we find that BBN constraints on hadronic annihilation channels are competitive with similar bounds derived from the cosmic microwave backgr…
Hadronic events in $e^+ e^- \to Z^0$ are generated by a Monte-Carlo model including the production of colour separate states. These events are compared with those produced by the JETSET with default set of parameters where the colour connections are colour singlet chains. By selecting two-jet-like events and a sensitive observable, we find that these two kinds of colour connections lead to significant differences in the hadronic states.
We present a determination of the strong coupling constant from a fit of QCD predictions for six event-shape variables, calculated at next-to-next-to-leading order (NNLO) and matched to resummation in the next-to-leading-logarithmic approximation (NLLA). These event shapes have been measured in e+e- annihilations at LEP, where the data we use have been collected by the ALEPH detector at centre-of-mass energies between 91 and 206 GeV. Compared to purely fixed order NNLO fits, we observe that the central fit values are hardly affected, but the systematic uncertainty is larger because the NLLA pa…
We replace in the event generator JETSET the color singlet chain connection with the color separate state one as the interface between the hard and soft sectors of hadronic processes. The modified generator is applied to produce the hadronic events in $e^+ e^-$ annihilation. It describes the experimental data at the same level as the original JETSET with default parameters. This should be understood as a demonstration that color singlet chain is not the unique color connection. We also search for the difference in special sets of three-jet events arising from different color connections, which…
We consider a new technique for neutrino energy and topology reconstruction at DUNE. In particular, we show that when the direction of the incoming neutrino is known, one can use the measured directions of the outgoing leptonic and hadronic particles to reconstruct poorly-measured quantities, such as the hadronic cascade energy. We show that this alternative technique yields an energy resolution which is comparable to current reconstruction methods which sum measured energies. As a proof of concept we apply this new reconstruction method to a search for dark matter annihilation in the Sun. We …
We investigate the Glauber divergences in nonfactorizable annihilation amplitudes for two-body hadronic heavy meson decays in the $k_T$ factorization theorem at one-loop level. These divergences can be absorbed into the Glauber factors in the dominant kinematic regions of small parton momenta, which modify the interference between a nonfactorizable annihilation amplitude and other amplitudes by rotating it with a phase. We postulate that only the Glauber effect associated with a pion is significant, due to its special role as a $q\bar q$ bound state and as a pseudo Nambu-Goldstone boson simult…
We analyze the relativistic corrections to annihilation rates of S-wave quarkonia within the framework of NRQCD. We show that order v^2 corrections can be expressed in terms of the heavy quark pole mass and the quarkonium mass. The ratio of hadronic to radiative annihilation rates for eta_b and eta_c can therefore be predicted accurately. The contributions of color-octet operators to the hadronic decay rates of spin-triplet quarkonia are shown to be significant, even though they arise at order v^4 in the velocity expansion. We provide a rough estimate of the color-octet contributions and extra…
We compute the cross section for exclusive production of a photon associated with a heavy quarkonium H of charge-conjugation parity C=+1 from e+ e- annihilation into a virtual photon at the center-of-momentum energy root-s=10.58 GeV. The NRQCD factorization formulas for the differential and total cross sections are obtained at leading order in the strong coupling and in the relative velocity of the heavy quark in the quarkonium rest frame. The predicted cross sections for the S-wave spin-singlet cases are about 80 fb and 50 fb for H = eta_c and eta_c(2S), respectively. Among P-wave spin-triple…
A mathematical formalism for the analysis of correlations in multi-source events such as $W^+W^-$ production in $e^+e^-$ annihilations is presented. Various measures used in experimental searches for inter-$W$ correlations are reviewed.
In this paper we study CP violation in $B\to PP$ decays in the Standard Model using SU(3) flavor symmetry. With SU(3) symmetry only seven hadronic parameters are needed to describe $B\to PP$ decays in the SM when annihilation contributions are neglected. The relevant hadronic parameters can be determined using known experimental data from $B\to ππ$ and $B\to K π$. We predict branching ratios and CP asymmetries for some of the unmeasured $B \to PP$ decays. Some of the CP asymmetries can be large and measured at B factories. The effects of annihilation contributions can also be studied using pre…
Hypothetical long-lived massive colored particles (MCPs or Ys) would be confined in colorless exotic strongly interacting massive particles (SIMPs) at color confinement temperature of T_C /sim 200 MeV. Two long-lived MCPs form a bound state (Y /bar{Y}) at collisions of two SIMPs. We study sensitivities of MCP annihilation to decay properties of resonances (Y /bar{Y}), and binding energies or energy levels of exotic SIMPs. The (Y /bar{Y}) formation is assumed to dominantly proceeds through resonances of (Y/bar{Y}) in this paper. We make a toy model of the effective cross section for Y /bar{Y} a…
The nearly energy independent hadron emitter dimension $r$, measured in $e^+e^-$ annihilation in the energy range 10 to 91 GeV via the Bose-Einstein correlation of two identical charged pions, is shown to be well accounted for by choosing the hadron jets as independent pion sources. To this end the known normalised factorial cumulant moments dependence on particle sources is adapted to the Bose-Einstein correlation formalism to yield a relation between $r$ and these sources. This approach is also able to account for the measured $r$ values obtained for the $Z^0$ decays into two and three hadro…
We study inelastic meson-meson scattering that is governed by quark-antiquark annihilation and creation involving a quark and an antiquark annihilating into a gluon, and subsequently the gluon creating another quark-antiquark pair. The resultant hadronic reactions include for I=1: pion + pion to rho + rho, kaon + antikaon to kaon* + antikaon*, kaon + antikaon* to kaon* + antikaon*, kaon* + antikaon to kaon* + antikaon*, as well as pion + pion to kaon + antikaon, pion + rho to kaon + antikaon*, pion + rho to kaon* + antikaon, and kaon + antikaon to rho + rho. In each reaction, one or two Feynma…
Recent improvements in the low energy e+e- annihilation data and their influence on the determination of the hadronic contribution to the running of the QED fine structure constant at m_Z are discussed. Using CMD-2 and KLOE measurements in the rho region we obtain Delta alpha(5)_had(s) = 0.02758 +/- 0.00035 at s = m_Z^2.
We discuss challenges to a dark matter annihilation interpretation of the excess positron fraction in the cosmic rays observed by the PAMELA, Fermi-LAT and AMS-02 collaborations. The spectra of positrons from annihilations into the leptonic two-body final states like $τ^+ τ^-$ or $μ^+ μ^-$, fit well the AMS-02 data for the positron ratio and the electron flux. Furthermore, we discuss the hadronic annihilation channels $b \bar{b}$ and $W^+ W^-$. However, this interpretation requires a very large annihilation cross section especially for the hadronic channels, conflicting with the unitarity uppe…
