In this letter we suggest that the obvious discrepancy between theoretical prediction on the $\mathrm{non}-D\bar D$ decays of $ψ(3770)$ and data is to be alleviated by taking final state interaction (FSI) into account. By assuming that $ψ(3770)$ overwhelmingly dissociates into $D\bar D$, then the final state interaction induces a secondary process, we calculate the branching ratios of $ψ(3770)\to D\bar D\to J/ψη, ρπ, ωη, K^*K$. Our results show that the branching ratio of $ψ(3770)\to \mathrm{non}-D\bar{D}$ can reach up to $\mathcal{B}_{\mathrm{non}-D\bar{D}}^{FSI}=(0.2\sim1.1)%$ while typical parameters $I=0.4$ GeV$^{-2}$ and $α=0.8\sim 1.3$ are adopted. This indicates that the FSI is obviously non-negligible.
The strange quark polarization puzzle, i.e. the contradiction between the negative polarized strange quark density obtained from analyses of inclusive DIS data and the positive values obtained from combined analyses of inclusive and semi-inclusive SIDIS data using de Florian et. al. (DSS) fragmentation functions, is discussed. To this end the results of a new combined NLO QCD analysis of the polarized inclusive and semi-inclusive DIS data, using the Hirai et. al. (HKNS) fragmentation functions, are presented. It is demonstrated that the polarized strange quark density is very sensitive to the …
The fact that analyses of semi-inclusive deep inelastic scattering suggest that the polarized strange quark density $Δs(x) + Δ\bar{s}(x)$ is positive in the measured region of Bjorken x, whereas all analyses of inclusive deep inelastic scattering yield significantly negative values of this quantity, is known as the "strange quark polarization puzzle". We have analyzed the world data on inclusive deep inelastic scattering, including the COMPASS 2010 proton data on the spin asymmetries, and for the first time, the new extremely precise JLab CLAS data on the proton and deuteron spin structure fun…
Our analysis suggests that the charmless yield in B decays is enhanced over traditional estimates. The c c.bar pair produced in b to c c.bar transitions may be seen significantly as light hadrons due to non-perturbative effects. Existing data samples at Upsilon(4S) and Z^0 factories allow key measurements which are outlined.
Recent analyses of flavor-breaking hadronic-$τ$-decay-based sum rules produce values of $\vert V_{us}\vert$ $\sim 3σ$ low compared to 3-family unitarity expectations. An unresolved systematic issue is the significant variation in $\vert V_{us}\vert$ produced by different prescriptions for treating the slowly converging $D=2$ OPE series. We investigate the reliability of these prescriptions using lattice data for various flavor-breaking correlators and show the fixed-scale prescription is clearly preferred. Preliminary updates of the conventional $τ$-based, and related mixed $τ$-electroproducti…
Some long-standing problems in the experimental data for semileptonic b -> c l nu decay rates have resisted attempts to resolve them, despite substantial efforts. We summarize the issues, and propose a possible resolution, which may alleviate several of these tensions simultaneously, including the "1/2 vs. 3/2 puzzle" and the composition of the inclusive decay rate in terms of exclusive channels.
We revisit the puzzle of $|V_{us}|$ values obtained from the conventional implementation of hadronic-$τ$-decay-based flavor-breaking finite-energy sum rules lying $>3 σ$ below the expectations of three-family unitarity. Significant unphysical dependences of $|V_{us}|$ on the choice of weight, w, and upper limit, $s_0$, of the experimental spectral integrals entering the analysis are confirmed, and a breakdown of assumptions made in estimating higher dimension, $D>4$, OPE contributions is identified as the main source of these problems. A combination of continuum and lattice results is shown to…
Continuum and lattice methods are used to investigate systematic issues in the sum rule determination of $V_{us}$ using inclusive hadronic $τ$ decay data. Results for $V_{us}$ employing assumptions for $D>4$ OPE contributions used in previous conventional implementations of this approach are shown to display unphysical dependence on the sum rule weight, $w$, and choice of upper limit, $s_0$, of the relevant experimental spectral integrals. Continuum and lattice results suggest a new implementation of the sum rule approach with not just $\vert V_{us}\vert$, but also $D>4$ effective condensates,…
We present here an extraction of the jet transport coefficient, $\hat{q}$, using RHIC and LHC single-inclusive high-$p_T$ data for different centralities. We fit a $K$-factor that determines the deviation of this coefficient from an ideal estimate, $K \equiv \hat{q}/(2ε^{3/4})$, where $ε$ is given by hydrodynamic simulations. As obtained already in previous studies, this $K$-factor is found to be larger at RHIC than at the LHC. However it is, unexpectedly, basically no-dependent on the centrality of the collision. Taken at face value this result, the $K$-factor would not depend on local proper…
We discuss the impact of the recent untagged analysis of ${B}^0\rightarrow D^{*}l\barν_l$ decays by the Belle Collaboration on the extraction of the CKM element $|V_{cb}|$ and provide updated SM predictions for the $b\to cτν$ observables $R(D^*)$, $P_τ$, and $F_L^{D^*}$. The value of $|V_{cb}|$ that we find is about $2σ$ from the one from inclusive semileptonic $B$ decays, and is very sensitive to the slope of the form factor at zero recoil which should soon become available from lattice calculations.
A combination of continuum and lattice methods is used to investigate systematic issues in the finite-energy-sum-rule determination of $V_{us}$ based on flavor-breaking combinations of hadronic $τ$ decay data. Results for $V_{us}$ obtained using assumptions for $D>4$ OPE contributions employed in previous conventional implementations of this approach are shown to display significant unphysical dependences on the choice of sum rule weight, $w$, and upper limit, $s_0$, of the relevant experimental spectral integrals. Continuum and lattice results suggest the necessity of a new implementation of …
In recent studies of inclusive $B$ decays, it has been suggested that either $B$ mesons decay much more copiously to final states with no open charm than currently assumed, or $B(D^0 \to K^-π^+)$ has to be reduced significantly. This note takes the experimental $B(D^0 \to K^-π^+)$ at its face value and estimates $B(b\to$ no open charm) using complementary methods: one accounts for the $c$ quark in $b\to c$ transitions, the other accounts for the $\bar c$ quark in $b\to c\bar c s$ transitions. Through cancellation of errors, the average gives our best estimate of $B(b\to$ no open charm), and th…
The status of the heavy quark expansion for inclusive B decays is briefly reviewed from the perspective of confronting theory with data and of extracting the heavy quark parameters. A good agreement between properly applied theory and new precision data is observed. Some recent applications to the exclusive heavy flavor transitions are addressed. I recall the `1/2 > 3/2' paradox for the transitions into the charm P-wave states.
It is demonstrated that charm is systematically undercounted in various experiments. Via a process of elimination, $B(D^0 \rightarrow K^- π^+ )$ is identified as the culprit. It calibrates essentially all charmed meson production and decay properties, and thus is central to the physics of heavy flavors. We predict it to decrease significantly below currently accepted values. We suggest several novel methods for precise measurements of $B(D^0 \rightarrow K^- π^+ )$. The $B(Λ_c \rightarrow pK^-π^+)$, on the other hand, calibrates heavy-flavored baryons. Its world average relies heavily on a mode…
Inclusive and exclusive semileptonic decays of heavy mesons on the lattice
High Energy Accelerator Research Organization (KEK)（高能加速器研究机构）；University of Southampton（南安普顿大学）；SOKENDAI (The Graduate University for Advanced Studies)（高级研究院索卡代）；CERN（欧洲核子研究中心）
We explain the origin of the difficulties that appear in a straightforward application of the QRPA in C(12), and we demonstrate that it is imperative to use the projected QRPA (PQRPA). Satisfactory results, not only for the weak processes among the ground states of the triad B(12),C(12),N(12), but also for the inclusive ones are obtained. We sketch as well a new formalism for the neutrino-nucleus interaction that furnishes very simple final formulae for the muon capture rate and neutrino induced cross sections.
Normalizing the recent LHCb measurement of $Λ_b \to Λ_c τ\barν$ to the standard model (SM) prediction for the $Λ_b \to Λ_c μ\barν$ rate, instead of a LEP measurement, provides a more consistent comparison with the SM prediction for the lepton flavor universality ratio $R(Λ_c)$. This modestly increases $R(Λ_c)$ compared to the quoted LHCb result, such that it no longer hints at a suppression compared to the SM, which would be hard to accommodate in new physics scenarios that enhance $R(D^{(*)})$. We point out that the fraction of excited states in inclusive semileptonic $Λ_b$ decay may be signi…
We examine the so-called rho-pi puzzle of the psi(2S) decay by incorporating two inputs: One is the relative phase between the one-photon and the gluon decay amplitude, and the other is a possible anomaly in the inclusive nonelectromagnetic decay rate of psi(2S). We propose the possibility that in the psi(2S) decay a hadronic decay process of long distance origin is important in addition to the short-distance decay process. The amplitude of this additional process should nearly cancel the three-gluon amplitude in the exclusive psi(2S)---> 1-0- and turn the sum dominantly real in contrast to th…
Understanding the composition of final states in $B \to X_c l ν$ could help to get a feedback on the persisting disagreement between exclusive and inclusive determinations of $V_{cb}$. In particular the series of orbital excitations $D^{**}$ and radial excitations ($D'$, $D^*\,'$) has received a lot of attention; a misinterpretation as a scalar state of the ($D' \to D π$) spectrum tail could have induced an experimental overestimate of the broad states contribution to the total $B \to X_c l ν$ width with respect to theoretical expectations, all of them made however in the infinite mass limit: …
Nonrelativistic QCD provides a systematic approach for inclusive decays and productions of a quarkonium. By taking color-octet components into account, the approach can explain the $ψ'$-anomaly at Tevatron, where the measured production rate at large transverse momentum $p_\perp$ is in order of magnitude larger than the predicted with color-singlet components only. With the approach one can predict that the produced $J/ψ$ and $ψ'$ at large $p_\perp$ will be transversely polarized. But the prediction fails in confronting with experimental measurements and this generates a puzzle. We examine the…
QED gauge invariance, when combined with analyticity, leads to constraints on the low energy end of the emitted photon spectra. This is known as Low's theorem. It is shown that the Ore-Powell result, as well as further developments for the orthopositronium differential decay rate, are in contradiction with Low's theorem, i.e. that their predicted soft photon spectra are incorrect. A solution to this problem is presented. The implications for the orthopositronium lifetime puzzle, the charmonium rho-pi puzzle, the prompt photon spectrum in inclusive quarkonium decays and the extraction of alpha_…
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…
The inclusive decay rate into pions of the charmed $D_s$ meson is surprisingly larger than estimates expected from the $W$ annihilation, adopting commonly used values of current-algebra up and down quark masses. We then go beyond this tree diagram and consider possible QCD effects that might cause such a large rate. There are two; the first one is related to the spectator decay $ c{\bar s} \rightarrow s{\bar s} + u {\bar d}$ followed by $ s {\bar s} \rightarrow d{\bar d}~,~ u{\bar u}$ via two-gluon exchange box diagram. The second one is a gluon emission in weak annihilation for which the usua…
e+e- Experiments producing charmonium are reviewed. It is found that the contribution of the continuum amplitude via virtual photon was neglected in almost all the experiments and the channels analyzed. It is shown that the contribution of the continuum part may affect the final results significantly in psi(2S) and psi(3770) decays, while the interference between continuum and resonance amplitudes may even affect the J/psi decays as well as the psi(2S) and psi(3770). This should be considered in analyzing the "rho-pi puzzle" between J/psi and psi(2s) decays, and the difference between inclusiv…
We calculate the contributions of penguin diagrams with internal u or c quarks to various inclusive charmless B-decay rates. Further we analyze the influence of the chromomagnetic dipole operator Q_8 on these rates. We find that the rates corresponding to B-bar --> X_{u u-bar s}, B-bar --> X_{d d-bar s}, B-bar --> X_{s s-bar s}, B-bar --> X_{s s-bar d} and B --> X_{d d-bar d} are dominated by the new penguin contributions. The contributions of Q_8 sizably diminish these rates. Despite of an increase of the total charmless decay rate by 36 % the new contributions are not large enough to explain…
The OPE treatment that has been so successful in describing inclusive $\bar B \to l \bar νX_c$ decays yields sum rules (in particular the Uraltsev sum rule and its higher moments) implying the dominance of the $P$ wave $j_q = 3/2$ charm states in $X_c$ over their $j_q=1/2$ counterparts. This prediction is supported by other general arguments as well as quark model calculations, which illustrate the OPE results, and by preliminary lattice findings. Its failure would indicate a significant limitation in our theoretical understanding of $\bar B \to l \bar νX_c$. Some experimental issues have been…
Inclusive $B$ decays, lifetimes, and $|V_{cb}|$: a unified heavy-quark expansion analysis
Università di Padova（帕多瓦大学）；Istituto Nazionale di Fisica Nucleare, Sezione di Padova（意大利国家核物理研究所帕多瓦分部）；Universität Siegen（锡根大学）；University of Bonn（波恩大学）；Maastricht University（马斯特里赫特大学）；Nikhef（荷兰国家亚原子物理研究所）
Conflicting values of the hypertriton ($_Λ^{3}$H) lifetime were extracted in recent relativistic heavy-ion collision experiments. The ALICE Collaboration's reported $_Λ^{3}$H lifetime $τ(_Λ^{3}$H) is compatible within measurement uncertainties with the free $Λ$ lifetime $τ_Λ$, as naively expected for a loosely bound $Λ$ hyperon in $_Λ^{3}$H, whereas STAR's reported range of $τ(_Λ^{3}$H) values is considerably shorter: $τ_{\rm STAR}(_Λ^{3}$H)$\sim$(0.4-0.7)$τ_Λ$. This $_Λ^{3}$H lifetime puzzle is revisited theoretically using $_Λ^{3}$H three-body wavefunctions generated in a chiral effective fi…
The so-called ρπpuzzle of Jψand ψ(2S) decays is examined using the experimental data available to date. Two different approaches were taken to estimate the ratio of Jψand ψ(2S) hadronic decay rates. While one of the estimates could not yield the exact ratio of ψ(2S) to Jψinclusive hadronic decay rates, the other, based on a computation of the inclusive ggg decay rate for ψ(2S) (Jψ) by subtracting other decay rates from the total decay rate, differs by two standard deviations from the naive prediction of perturbative QCD, even though its central value is nearly twice as large as what was naivel…
Two of the elements of the Cabibbo-Kobayashi-Maskawa quark mixing matrix, $|V_{ub}|$ and $|V_{cb}|$, are extracted from semileptonic B decays. The results of the B factories, analysed in the light of the most recent theoretical calculations, remain puzzling, because for both $|V_{ub}|$ and $|V_{cb}|$ the exclusive and inclusive determinations are in clear tension. Further, measurements in the $τ$ channels at Belle, Babar, and LHCb show discrepancies with the Standard Model predictions, pointing to a possible violation of lepton flavor universality. LHCb and Belle II have the potential to resol…
e+e- experiments at charmonium production threshold are reviewed, it is found that the contribution of the continuum process via virtual photon has been neglected in almost all the experiments and most channels analyzed. It is pointed out that the contribution of the continuum part may affect the final results significantly in psi(2S) and psi(3770) decays, while the interference between the continuum amplitude and the resonance amplitude may even affect the J/psi decays as well as the psi(2S) and psi(3770). This leads to the revise of the analysis of strong and electromagnetic amplitude in psi…
We reemphasize that the ratio $R_{sμ} \equiv \overline{\mathcal{B}}(B_s\toμ\barμ)/ΔM_s$ is a measure of the tension of the Standard Model (SM) with latest measurements of $\overline{\mathcal{B}}(B_s\toμ\barμ)$ that does not suffer from the persistent puzzle on the $|V_{cb}|$ determinations from inclusive versus exclusive $b\to c\ell\barν$ decays and which affects the value of the CKM element $|V_{ts}|$ that is crucial for the SM predictions of both $\overline{\mathcal{B}}(B_s\toμ\barμ)$ and $ΔM_s$, but cancels out in the ratio $R_{sμ}$. In our analysis we include higher order electroweak and Q…
Conflicting values of the hypertriton lifetime $τ({}_Λ^3\mathrm{H})$ were derived in relativistic heavy ion (RHI) collision experiments over the last decade. A very recent ALICE Collaboration measurement is the only experiment where the reported $τ({}_Λ^3\mathrm{H})$ comes sufficiently close to the free-$Λ$ lifetime $τ_Λ$,as expected naively for a very weakly bound $Λ$ in ${}_Λ^3\mathrm{H}$. We revisited theoretically this ${}_Λ^3\mathrm{H}$ lifetime puzzle, using ${}_Λ^3\mathrm{H}$ and ${}^3\mathrm{He}$ wave functions computed within the abinitio no-core shell model employing interactions der…
$|V_{cb}|$ determinations from $\bar{B} \to D^{(*)} \ell \barν$ decays within the SM and beyond
Central China Normal University（华中师范大学）；Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics (MOE), Central China Normal University（粒子物理与夸克轻子物理重点实验室（教育部），华中师范大学）；Nagoya University（名古屋大学）；Institute for Advanced Research (IAR), Nagoya University（名古屋大学高等研究院）；Kobayashi-Maskawa Institute (KMI) for the Origin of Particles and the Universe, Nagoya University（名古屋大学小林-益川粒子起源宇宙研究所）
