We have studied color-octet contributions for $J/ψ$ inclusive production at B factories, i.e., $e^+e^-\to J/ψ(^3P_J^{[8]},^1S_0^{[8]}) + X_{\mathrm{non}-c\bar c}$, using the soft gluon factorization (SGF) approach, in which the $J/ψ$ energy spectrum is expressed in a form of perturbatively calculable short-distance hard parts convoluted with one-dimensional soft gluon distributions (SGDs). The series of velocity corrections originated from kinematic effect can be naturally resummed in this approach. Short-distance hard parts have been calculated analytically to next-to-leading order in $α_s$. Renormalization group equations for SGDs have been derived and solved, which resums Sudakov logarithms originated from soft gluon emissions. Our final result gives a upper bound for color-octet matrix elements consistent with that extracted from hadron colliders. This may relieve the well-known universality problem in the NRQCD factorization.
As a comparison, we also analytically calculated short-distance hard parts in the NRQCD factorization, with Sudakov logarithms resummed by using soft collinear effective theory. The comparison shows that velocity corrections from kinematic effect, which have been resummed in SGF, are significant for phenomenological study. Furthermore, it is found that Sudakov logarithms originated from soft gluon emissions are very important, while it is not the case for Sudakov logarithms originated from jet function. Therefore, the partial Sudakov resummation in SGF has already captured the main physics.
Double $J/ψ$ production in $e^+e^-$ collisions involving colour-octet channels are evaluated up to order $α^2α_s^3$. Having implemented the variation of the parameters ($m_c$, $μ_r$ and long-distance matrix elements), we found that the cross sections for producing double $J/ψ$ at B-factories range from $-0.016$fb to $0.245$fb, which are even much smaller than that via the colour-siglet mechanism. Accordingly, this result is consistent with the measurement by the Belle and BABAR Collaborations.
Within the nonrelativistic QCD (NRQCD) factorization framework, we investigate the inclusive production of the $h_c$ meson associated with either light hadrons or charmed hadrons at $B$ factory energy $\sqrt{s}=10.58$ GeV. Both the leading color-singlet and color-octet channels are included. For the $h_c$ production associated with light hadrons, the total production rate is dominated by the color-octet channel, thus the future measurement of this process may impose useful constraint on the value of the color-octet matrix element $<{\cal O}^{h_c}_8({}^1S_0)>$; for the $h_c$ production associat…
We calculate the relativistic correction to $J/ψ$ production in the color-singlet process $e^{+}e^{-}\to J/ψ+gg$ at B-factories. We employ the non-relativistic QCD (NRQCD) factorization approach, where the short-distance coefficients are calculated perturbatively and the long-distance matrix elements are extracted from the decays of $J/ψ$ into $e^{+}e^{-}$ and light hadrons. We find that the $O(v^2)$ relativistic correction can enhance the cross section by a factor of 20-30%, comparable to the enhancement due to the $O(α_s)$ radiative correction obtained earlier. Combining the relativistic cor…
In nonrelativistic Quantum Chromodynamics (NRQCD), we study the next-to-leading order (NLO) QCD radiative correction to the color-octet $J/ψ$ inclusive production at B Factories. Compared with the leading-order (LO) result, the NLO QCD corrections are found to enhance the short-distance coefficients in the color-octet $J/ψ$ production $ e^+ e^-\to c \bar c (^3P_0^{(8)} {\rm or} ^3P_0^{(8)})g$ by a factor of about 1.9. Moreover, the peak at the endpoint in the $J/ψ$ energy distribution predicted at LO can be smeared by the NLO corrections, but the major color-octet contribution still comes from…
The next-to-leading order (NLO) quantum chromodynamics (QCD) corrections for $χ_{cJ}(^3P_J^{[1]},^3S_1^{[8]})$, the P-wave charmoniums inclusive production at $B$ factories are calculated utilizing the non-relativistic QCD (NRQCD) factorization formalism. Large NLO corrections are found, especially for $^3P_0^{[1]}$ and $^3S_1^{[8]}$ configurations. Numerical evaluation indicates that the total cross sections of $χ_{cJ}$ inclusive production processes are at the order of $10$fb, which are accessible in BELLE II(super-B) experiment.
Measurements by the Belle Collaboration of the exclusive J/psi + eta_c and inclusive J/psi +cc-bar+X productions in e^+ e^- annihilation differ substantially from theoretical predictions based on the nonrelativistic QCD factorization approach. In order to test if such a discrepancy is originated from the large perturbative corrections to the hard-scattering amplitude, we study inclusive production of four charm hadrons in e^+e^- annihilation at B factories.
At existing and planned neutrino factories (high energy and high intensity neutrino beam facilities) precision studies of QCD in neutrino-nucleon interactions are a realistic opportunity. We investigate charmonium production in fixed target neutrino experiments. We find that $J/ψ$ production in neutrino-nucleon collision is dominated by the color octet $^3S_1$ NRQCD matrix element in a neutral current process, which is not accessible in photo or leptoproduction. Neutrino experiments at a future Muon Collider will acquire sufficient event rate to accurately measure color octet matrix element co…
Calculations for inclusive J/psi production in Upsilon decay through the color-octet mechanisms b\bar b[^3S_1, 1] -> c \bar c[^{2s+1}L_J, 8] + g are presented. It is shown that these O(alpha^5_sv^4_c) contributions compete with other color-octet mechanisms considered in the literature. A critical numerical analysis of the color-octet contributions to Upsilon -> J/psi + X shows that further work in this channel, both theoretical and experimental, is necessary in order to clearly understand the significance of the color-octet component of the c \bar c component inside the J/psi system.
We discuss the determination of the CKM phase gamma through the decay B- -> K- D0 and related processes. In particular, we consider the use of this methods when the D0 subsequently decays to an inclusive state. We emphasize that strong phase information obtained at a psi(3770) charm factory can provide additional information which will be helpful in determining gamma.
In order to clarify the puzzling problems in double charm production, relativistic corrections at order $v^{2}$ to the processes $e^{+}e^{-}\to J/ψ+η_{c}$ and $e^{+}e^{-}\to J/ψ+c\bar{c}$ at B factories are studied in non-relativistic quantum chromodynamics. The short-distance parts of production cross sections are calculated perturbatively, while the long-distance matrix elements are estimated from $J/ψ$ and $η_c$ decays up to errors of order $v^4$. Our results show that the relativistic correction to the exclusive process $e^{+}e^{-}\to J/ψ+η_{c}$ is significant, which, when combined togethe…
We propose a program at B-factories of inclusive, multi-track displaced vertex searches, which are expected to be low background and give excellent sensitivity to non-minimal hidden sectors. Multi-particle hidden sectors often include long-lived particles (LLPs) which result from approximate symmetries, and we classify the possible decays of GeV-scale LLPs in an effective field theory framework. Considering several LLP production modes, including dark photons and dark Higgs bosons, we study the sensitivity of LLP searches with different number of displaced vertices per event and track requirem…
Based on Monte Carlo techniques, we analyze the initial state radiation (ISR) effects in prompt $\jpsi$ inclusive production at B factories. ISR enhances cross section $σ(e^-e^+\to\jpsi+gg+X)$ by about $15-25\%$, which is almost the same size as the QCD and relativistic correction. Moreover, ISR slightly changes $σ(e^-e^+\to\jpsi+c\bar{c}+X)$. The $\jpsi$ momentum spectrum in $e^-e^+\to\jpsi+gg+X$ and in $e^-e^+\to\jpsi+c\bar{c}+X$ is softer after the photon showering from the initial $e^{\pm}$ beam radiation. After combining the QCD,relativistic, and ISR corrections,a more precise theoretical…
We study the first-order relativistic correction to the associated production of $J/ψ$ with light hadrons at $B$ factory experiments at $\sqrt{s}=10.58$ GeV, in the context of NRQCD factorization. We employ a strategy for NRQCD expansion that slightly deviates from the orthodox doctrine, in that the matching coefficients are not truly of ``short-distance" nature, but explicitly depend upon physical kinematic variables rather than partonic ones. Our matching method, with validity guaranteed by the Gremm-Kapustin relation, is particularly suited for the inclusive quarkonium production and decay …
We calculate the next-to-leading order (NLO) radiative correction to the color-octet $h_c$ inclusive production in $e^+e^-$ annihilation at Super $B$ factory, within the nonrelativistic QCD factorization framework. The analytic expression for the NLO short-distance coefficient (SDC) accompanying the color-octet production operator $\mathcal{O}_8^{h_c}(^1S_0)$ is obtained after summing both virtual and real corrections. The size of NLO correction for the color-octet production channel is found to be positive and substantial. The NLO prediction to the $h_c$ energy spectrum is plagued with unphys…
The inclusive D-wave charmonium production rates in B decays are considered in the Bodwin-Braaten-Lepage (BBL) approach. We find that the color-octet subprocesses B->cc_(^3S_1^(8) or ^3P_J^(8))+s,d, followed by the transition cc_(^3S_1^(8) or ^3P_J^(8)) -> ^3D_J, strongly dominate over any other subprocess, due to the large Wilson coefficient for the ΔB = 1 effective lagrangian. Assuming that the numerical values of the matrix elements <0|O^{^3D_J}(^3S_1^(8))|0> and <0|O^{^3D_J}(^3P_J^(8))|0> are the same order of magnitudes with the <0| O^{ψ^'}(^3S_1^(8))|0>, we find that the ^{1,3}D_{2} can …
We analyze the end-point region of the photon spectrum in semi-inclusive radiative decays of very heavy quarkonium (m alpha_s^2 >> Lambda_QCD). The S- and P-wave octet shape functions are calculated. When they are included in the analysis of the photon spectrum of the Upsilon (1S) system the agreement with data becomes excellent.
Working in the nonrelativistic-QCD factorization framework at next-to-leading order in $α_s$, we fit the relevant color octet (CO) long-distance matrix elements (LDMEs) of the $ψ(2S)$ meson, $\langle {\cal O}^{ψ(2S)}({^1S}_0^{[8]})\rangle$, $\langle {\cal O}^{ψ(2S)}({^3S}_1^{[8]})\rangle$, and $\langle {\cal O}^{ψ(2S)}({^3P}_0^{[8]})\rangle$, to 1001 data points of upolarized and polarized $ψ(2S)$ inclusive hadroproduction. We do four different fits, with filters on polarization and low to middle transverse momentum $p_T$. We find that a successful description of the data is only possible with…
It is suggested that the measurements of hadronic invariant mass ($m_X$) distributons in the inclusive $B \rightarrow X_{c(u)} l ν$ decays can be useful in extracting the CKM matrix element $|V_{ub}|$. We investigated hadronic invariant mass distributions within the various theoretical models of HQET, FAC and chiral lagrangian as well as ACCMM model. It is also emphasized that the $m_X$ distribution even at the region $m_{X} > m_{D}$ in the inclusive $b\rightarrow u$ are effetive in selecting the events, experimentally viable at the future asymmetric $B$ factories, with better theoretical unde…
In inclusive P-wave charmonium decay, to cancel infrared divergence in the colour singlet contribution requires the inclusion of the colour octet which becomes degenerate with the former in the infrared limit. In the corresponding exclusive decay, such an infrared divergence does not exist. On this ground, it becomes doubtful whether the colour octet is needed in exclusive reactions. A contradiction in the underlying picture, however, would result once all strong decay channels are summed. We provide an answer to this question in support of the colour octet with theoretical arguments as well a…
We present a complete study of the associated production of the $η_c$ meson with light hadrons in $e^+e^-$ collisions at the B-factory energy, which is demonstrated to be one of the best laboratories for testing the colour-octet (CO) mechanism. The colour-siglet contributions are evaluated up to $O(α^2α_s^3)$ while the CO ones are evaluated up to $O(α^2α_s^2)$. For the first time, the angular distribution of the $^1S_0^{[8]}$ production is studied at QCD next-to-leading order. We find that the $^1S_0^{[8]}$ channel dominate the total cross section, while the $^1P_1^{[8]}$ one exhibit its impor…
To understand the direct $J/ψ+X_{\mathrm{non-c\bar{c}}}$ production mechanism in $e^{+}e^{-}$ annihilation, in this work, we propose to measure the inclusive $J/ψ$ plus light hadrons (LH) production at B-factories and present a detailed study on its QED production due to $ψ(2S)$ feed-down, where the $ψ(2S)$ are produced in $e^{+}e^{-}\to ψ(2S)+γ$ and $e^{+}e^{-}\to ψ(2S)+f\bar{f}, f=lepton,light quark$, and QED contribution to direct $J/ψ+q\bar{q}$ production with $q=u,d,s$ quark. We find that the QED contribution is huge in the whole phase space region, but can be reduced largely and is in th…
In the last years, the need of the colour octet state in inclusive P-wave charmonium decay has been firmly established. However, the implications of this in the corresponding exclusive reactions have not been fully recognized. We argue for the necessity of the colour octet in P- and higher-wave quarkonium decay. Using a set of phenomenologically constructed baryon wavefunctions, we consider the Chi_J decay into octet and decuplet baryon-antibaryon pair. By doing so, we subject the wavefunctions to a test of applicability. We show that the colour singlet component alone is insufficient to accou…
We compute the color-singlet and color-octet nonrelativistic QCD (NRQCD) long-distance matrix elements for inclusive production of $P$-wave quarkonia in the framework of potential NRQCD. In this way, the color-octet NRQCD long-distance matrix element can be determined without relying on measured cross section data, which has not been possible so far. We obtain inclusive cross sections of $χ_{cJ}$ and $χ_{bJ}$ at the LHC, which are in good agreement with data. In principle, the formalism developed in this Letter can be applied to all inclusive production processes of heavy quarkonia.
Measurements by the Belle Collaboration of the exclusive production of two charmonia in e^+ e^- annihilation differ substantially from theoretical predictions. Till now, no conclusive explanation for this remarkable discrepancy has been provided. Even the origin of the discrepancy is not identified, yet. We suggest that the measurement of four-charm events in Belle data must provide a strong constraint in identifying the origin of this large discrepancy. Our prediction of the cross section for e^+e^- -> c c-bar c c-bar, in lowest order in strong coupling constant, at sqrt{s}=10.6 GeV is about …
In the spirit of Mueller-Navelet dijet production, we propose and study the inclusive production of a forward $J/ψ$ and a very backward jet at the LHC as an observable to reveal high-energy resummation effects à la BFKL. We obtain several predictions, which are based on the various mechanisms discussed in the literature to describe the production of the $J/ψ$, namely, NRQCD singlet and octet contributions, and the color evaporation model.
Recently, Belle Collaboration has reported a resonant state produced in $B\to K πψ'$, which is called Z(4430). This state is charged, so it can not be interpreted as an ordinary charmonium state. In this paper, we analyze the octet to which this particle belongs and predict the masses of mesons in this octet. Utilizing flavor SU(3) symmetry, we study production rates in several kinds of B decays. The $\bar B^0\to Z_s^-π^+\to K^-ψ'π^+$ and $B^-\to \bar Z_s^0 π^-\to K_Sψ'π^-$ decay channels, favored by Cabibbo-Kobayashi-Maskawa (CKM) matrix elements, can have branching ratios of ${\cal O}(10^{-5…
Motivated by the recent observation of double charm quark pair production by the Belle Collaboration, we calculate the complete ${\cal O}(α_{s}^{2})$ inclusive production cross sections for $η_{c}$, $J/ψ$, and $χ_{cJ}$(J=0, 1, 2) plus $c\bar{c}$ in $e^+ e^-$ annihilation through a virtual photon. We consider both color-singlet and color-octet contributions, and give the analytical expressions for these cross sections. The complete color-singlet calculations are compared with the approximate fragmentation calculations as functions of the center-of-mass energy $\sqrt{s}$. We find that most of th…
The NLO QCD corrections to Upsilon production via S-wave color-octet states Upsilon(^1S_0^8,^3S_1^8) at the Tevatron and LHC is calculated. The K factors of total cross section (ratio of NLO to LO) are 1.313 and 1.379 for Upsilon(^1S_0^8) and Upsilon(^3S_1^8) at the Tevatron, while at the LHC they are 1.044 and 1.182, respectively. By fitting the experimental data from the D0, the matrix elements for S-wave color-octet states are obtained. And new predictions for Upsilon production are presented. The prediction for the polarization of inclusive Upsilon contains large uncertainty rising from th…
The inclusive $J/ψ$ production in $e^+ e^- \to J/ψc\bar c$ at B factories is one of the most challenging open problems in heavy quarkonium physics. The observed cross section of this double charm production process is larger than existing leading order (LO) QCD predictions by a factor of 5. In the nonrelativistic QCD (NRQCD) factorization formalism, we calculate the next-to-leading order (NLO) QCD virtual and real corrections to this process, and find that these corrections can substantially enhance the cross section with a $K$ factor of about 1.8. We further take into account the feeddown con…
The annihilation of the $B_c$ meson to leptons and inclusive light hadrons is analyzed in the framework of nonrelativistic QCD (NRQCD) factorization. We find that the decay mode, which escapes from the helicity suppression, contributes a sizable fraction width. According to the analysis, the branching ratio due to the contribution from the color-singlet component of the meson $B_c$ can be of order (10^{-2}). We also estimate the contributions from the color-octet components. With the velocity scaling rule of NRQCD, we find that the color-octet contributions are sizable too, especially, in cert…
We calculate the cross section of J/psi plus jet associated production in ep deep-inelastic scattering within the factorization formalism of nonrelativistic quantum chromodynamics. Our analytic results disagree with previous analyses, both for the colour-singlet and colour-octet channels. Our theoretical predictions agree reasonably well with recent data taken by the H1 Collaboration at DESY HERA, significantly better than those obtained within the colour-singlet model.
We propose and study the inclusive production of a forward $J/ψ$ and a very backward jet at the LHC as an observable to reveal high-energy resummation effects à la BFKL. Our different predictions are based on the various existing mechanisms to describe the production of the $J/ψ$, namely, NRQCD singlet and octet contributions, and the color evaporation model.
We compute the decay rates and $H$-energy distributions of $B$ mesons into the final state $H+X$, where $H$ can be any one of the $S$-wave or $P$-wave charmonia, at next-to-leading order in the strong coupling. We find that a significant fraction of the observed $J/ψ$, $ψ'$ and $χ_c$ must be produced through $c\bar{c}$ pairs in a colour octet state and should therefore be accompanied by more than one light hadron. At the same time we obtain stringent constraints on some of the long-distance parameters for colour octet production.
We investigate the pattern of asymmetries in the colour-octet model for inclusive production of charmonium with polarised initial state hadrons and photons. We find that singly polarised asymmetries vanish. The double polarised asymmetry for J/psi involves a new combination of long-distance matrix element. We also investigate the asymmetries for eta_c, chi_c and Upsilon production. The asymmetries distinguish well between different models of charmonium production.
Using information on B-meson fragmentation functions from CERN LEP 1 and adopting the nonrelativistic QCD factorization formalism proposed by Bodwin, Braaten, and Lepage, we predict the transverse-momentum distribution of J/psi mesons originating from the inclusive decays of b hadrons produced in p p-bar collisions at the Fermilab Tevatron. We determine the relevant colour-octet charmonium matrix elements from fits to CDF data on prompt charmonium hadroproduction and to CLEO data on charmonium production from B-meson decay. Our predictions are found to agree well with recent CDF and D0 data.
Based on the nonrelativistic QCD (NRQCD) factorization formalism, we investigate inclusive productions of two spin-triplet S-wave quarkonia pp->2J/psi+X, 2Upsilon+X, and J/psi+Upsilon+X at the CERN Large Hadron Collider. The total production rates integrated over the rapidity (y) and transverse-momentum (p_T) ranges |y|<2.4 and p_T<50 GGeV are predicted to be sigma[pp->2J/psi+X] = 22 (35) nb, sigma[pp->2Upsilon+X] = 24 (49) pb, and sigma[pp->J/psi+Upsilon+X] = 7 (13) pb at the center-of-momentum energy sqrt{s} = 7 (14) TeV. In order to provide predictions that can be useful in both small- and …
We calculate the inclusive decay rate of the spin-triplet bottomonium states chi_{bJ} into charm hadrons, including the leading-order color-singlet and color-octet bb-bar annihilation mechanisms. We also calculate the momentum distribution of the charm quark from the decay of chi_{bJ}. The infrared divergences from the color-singlet process bb-bar -> cc-bar g are factored into the probability density at the origin for a bb-bar pair in a color-octet state. That probability density can be determined phenomenologically from the fraction of decays of chi_{bJ} that include charm hadrons. It can the…
If the X(3872) is a loosely-bound D^{*0} Dbar^0 / D^0 Dbar^{*0} molecule, its inclusive production rate can be described by the NRQCD factorization formalism that applies to inclusive quarkonium production. We argue that if the molecule has quantum numbers J^{PC} = 1^{++}, the most important term in the factorization formula should be the color-octet ^3S_1 term. This is also one of the two most important terms in the factorization formulas for chi_{cJ}. Since the color-octet ^3S_1 term dominates chi_{cJ} production for many processes, the ratio of the inclusive direct production rates for X an…
Following Rosner [hep-ph/0312269], we consider B-decay production channels for the exotic I=0 and $I=3/2$ pentaquarks that have been recently reported. We also discuss new search channels for isovector pentaquarks, such as the $Θ^{*++} (\bar s duuu)$, that are generically present in chiral soliton models but were not observed in recent experiments. Futhermore, we argue that weak decays of charmed baryons, such as the $Λ_c^+$ and $Ξ_c^0$, provide another clean way of detecting exotic baryons made of light quarks only. We also discuss discovery channels for charmed pentaquarks, such as the isosi…
The semi-inclusive B-meson decay into spin-singlet D-wave $2^{-+}$ charmonium, $B\to η_{c2}+X$, is studied in nonrelativistic QCD (NRQCD). Both color-singlet and color-octet contributions are calculated at next-to-leading order (NLO) in the strong coupling constant $α_s$. The non-perturbative long-distance matrix elements are evaluated using operator evolution equations. It is found that the color-singlet $^1D_2$ contribution is tiny, while the color-octet channels make dominant contributions. The estimated branching ratio $B(B\to η_{c2}+X)$ is about $0.41\,\times10^{-4}$ in the Naive Dimensio…
Based on the non-relativistic QCD factorization formalism, we calculate the bottomonium ground state, $η_b$, inclusive charm decays at the leading order in the strong coupling constant $α_s$ and quarkonium internal relative velocity $v$. The inclusive charm pair production in $η_b$ decay is mainly realized through $η_b \to c \bar{c} g$ process, where the charm and anti-charm quarks then dominantly hadronize into charmed hadrons. The momentum distributions of the final states are presented. In this work, we also calculate the $J/ψ$ inclusive production rate in the $η_b$ decays, where the color-…
The importance of including colour octet contributions in describing decay and production of quarkonium states is briefly discussed for two cases : the radiative decays of the $Υ$ and the production of $J/ψ$ in the inclusive $B$ decays. It is shown how information on the non-perturbative matrix elements can be obtained by comparing the theoretical expressions computed at next-to-leading order in $α_s$ with the experimental data.
We calculate the cross section of inclusive direct J/psi photoproduction at next-to-leading order within the factorization formalism of nonrelativistic quantum chromodynamics, for the first time including the full relativistic corrections due to the intermediate ^1S_0^{[8]}, ^3S_1^{[8]}, and ^3P_J^{[8]} color-octet states. A comparison of our results to recent H1 data suggests that the color octet mechanism is indeed realized in J/psi photoproduction, although the predictivity of our results still suffers from uncertainties in the color-octet long-distance matrix elements.
We calculate the cross section of inclusive direct J/psi photoproduction at next-to-leading order within the factorization formalism of nonrelativistic quantum chromodynamics, for the first time including the full relativistic corrections due to the intermediate ^1S_0^[8], ^3S_1^[8], and ^3P_J^[8] color-octet states. A comparison of our results to recent H1 data suggests that the color octet mechanism is indeed realized in J/psi photoproduction, although the predictivity of our results still suffers from uncertainties in the color-octet long-distance matrix elements.
The implementation of various methods for the determination of gamma through direct CP violation arising in the interference of b->c and b->u processes in charged as well as neutral B meson decays are considered. We show that the inclusion of D0 resulting from D*0-->D0+pi0(gamma) say via B-->KD*0 makes a significant difference in the attainable accuracy for gamma. Both exclusive and inclusive decays of the B+- and B0 to states containing D0/D0-bar followed by both inclusive and exclusive decays of the D0 are discussed. It is shown that with statistics which might be obtained at B factories (5-…
The inclusive cross section for the production of $J/ψ$ in $e^+ e^-$ annihilation is studied using a recently developed factorization formalism. In addition to the conventional color-singlet contribution, we include contributions from $c \bar c$ pairs that are produced at short distances in color-octet states. The color-octet contributions are suppressed by the smaller probability for the color-octet $c \bar c$ pair to evolve into a state that includes a $ψ$, but they may dominate near the upper endpoint of the $ψ$ energy spectrum. The signature for the color-octet contribution is a dramatic c…
Color-octet mechanism for the decay B\to η^\prime X is proposed to explain the large branching ratio of Br(B\to η^\prime X)\sim 1\times 10^{-3} recently announced by CLEO. We argue that the inclusive η^\prime production in B decays may dominantly come from the Cabbibo favored b\to (\bar c c)_8s process where \bar c c pair is in a color-octet configuration, and followed by the nonperturbative transition (\bar c c)_8\to η^\prime X. The color-octet intrinsic charm component in the higher Fock states of η^\prime is crucial and is induced by the strong coupling of η^\prime to gluons via QCD axial a…
We show that although there is no infrared divergence in exclusive P-wave quarkonium decays, the colour octet contribution is no less important than in the inclusive decay. Results from more proper calculations with only colour singlet contribution are not sufficient to account for the measured partial decay widths and so the next higher Fock state must be included. Using the $\c_J$ decay into $N\bar N$ as an example, a scheme is devised to yield estimates of the decay widths using both contributions, the results are comparable with experimental measurements.
I discuss the impact of color-octet contributions to inclusive $J/ψ$ photoproduction at HERA. Emphasis is put on resolved photon processes and on $J/ψ$ polarization, which will be experimentally accessible at HERA in the near future. Both analyses provide a powerful test of the NRQCD factorization approach to charmonium production.
We study $c \bar c$ color-octet contribution to $B\to ψ(ψ') X$. When this contribution is included, the theoretical predictions for the branching ratios become in much better agreement with the experiment. This mechanism also enhances the partial rate asymmetries by about a factor of five. The inclusive $ψ(ψ')$ resulting from $b\to d+{}$gluon can have asymmetry around a few percent whereas those from $b\to s+{}$gluon has it around $4\times 10^{-4}$. The asymmetry in the former modes should be observable, to a significance of $3σ$, with about $(1-10)\times 10^8B$ mesons.
It is argued that colour octet contribution in exclusive charmonium decays is very important even though the same infrared divergence found in P-wave colour singlet inclusive decay is absent. This comes about because of the suppression at the level of the wavefunction of P-wave quarkonia. Using the modified hard scattering approach of Brodsky, Lepage, Botts, Li and Sterman, we use charmonium decay into baryon-antibaryon pair as an example and show that the colour singlet contribution alone is clearly insufficient to explain the experimental decay widths.
The inclusive $S-$wave charmonium production rates in $B$ decays are considered using the Bodwin-Braaten-Lepage (BBL) approach, including the relativistic corrections and the color-octet mechanism suggested as a possible solution to the $ψ^{'}$ puzzle at the Tevatron. We first consider relativistic and radiative corrections to $J/ψ\rightarrow e^{+} e^{-}$ and $J/ψ\rightarrow$ Light Hadrons (LH), in order to determine two nonperturbative parameters, $\langle J/ψ| O_{1} (^{3}S_{1}) | J/ψ\rangle$, $\langle J/ψ| P_{1} (^{3}S_{1}) | J/ψ\rangle$, in the factorization formulae for these decays. Using…
Recent advances in our understanding of the higher-wave quarkonia have generated much interests in quarkonium physics. However most are devoted to inclusive decays and productions. Experimental data of several two-body exclusive decay channels of P-wave charmonia such as ππand p \bar p are available and some have recently been re-measured by the BES collaboration. It is not clear from the outset that color octet is needed for these exclusive channels. Indeed only color singlet has been used in the past and reasonable agreement with data was found. Contrary to these old results, we provide theo…
J/ψproduction associated with a hard photon in e^+e^- annihilation, being of QED nature, is invastigated thoroughly in the paper. To show its influence on the observation of the color-octet singnature in the e^+e^- annihilation via J/ψinclusive production, the cross sections of the J/ψproductions through different mechanisms at various energies are compared quantatively by presenting them in figures together. The contribution from the production associated with a hard photon to the inclusive production of J/ψis pointed out to be significant at the concerned energies, thus the influence from it…
In this paper, the color-octet long distance matrix elements are studied though the inclusive $J/ψ$ production in $e^{+}e^{-}$ annihilation within the non-relativistic QCD frame. The calculations are up-to next-to-leading order with the radiative corrections and relativistic corrections at the B-factory energy region and the near-threshold region of $4.6\sim5.6~{\rm GeV}$. A constraint of the long distance matrix elements ($\langle^1S_0^{8}\rangle$, $\langle^3P_0^{8}\rangle$) is obtained. Through our estimation, the P-wave color-octet matrix element ( $\langle0|^3P^8_0|0\rangle$ ) should be th…
Inclusive bottomonium hadroproduction at the Tevatron is firstly examined in a Monte Carlo framework with the colour-octet mechanism implemented in the event generation. We extract some NRQCD colour-octet matrix elements relevant for $Υ(1S)$ hadroproduction. Remarkably we find a quite small contribution (compatible with zero) from feeddown of $χ_{bJ}$ states produced through the colour-octet mechanism: $Υ(1S)$ indirect production via $χ_{bJ}$ decays should be mainly ascribed to the colour-singlet model. Finally we extrapolate to LHC energies to predict prompt $Υ(1S)$ production rates.
We calculate the rates for inclusive hadronic decay of the three $χ_{bJ}$ states into a pair of light bottom squarks as a function of the masses of the bottom squark and the gluino. We include color-singlet and color-octet configurations. The color-octet contribution is found to be insignificant for the $χ_{b0}$ but can dominate in the $χ_{b2}$ case if current lattice estimates are used for the color-octet matrix element. In comparison with the standard model values, bottom squark decays can increase the predicted hadronic width of the $χ_{b0}$ by as much as 35%, for very small bottom squark m…
We study $J/ψ$ and $η_c$ inclusive production in $Υ$ decay within the framework of nonrelativistic-QCD (NRQCD) factorization. In the latter case, for which no experimental data exist so far, we also include the $h_c$ feed-down contribution. We calculate the short distance coefficients completely through $\mathcal{O}(α_s^5)$. The NRQCD predictions for the branching fraction $\mathcal{B}(Υ\to J/ψ+X)$ via direct production, evaluated with different sets of long-distance matrix elements (LDMEs), all agree with the experimental data in a reasonable range of renormalization scale. Using $η_c$ and $h…
In this paper, we present a comprehensive study of $Υ$ inclusive production in $Z$ boson decay, including the first complete next-to-leading-order calculations of the color-octet (CO) contributions. With the inclusion of the newly-calculated remarkable QCD corrections, the CO processes exhibit crucially phenomenological influence on the existing predictions built on the color-singlet mechanism. We also include the exhaustive evaluations of the feed-down contributions, which remained ignored in the literature, and find them to be considerable. Summing up all the contributions, the $\mathcal{B}_…
