Yu. S. Kalashnikova, A. V. Nefediev
Properties of the charmonium-like state X(3872) are investigated and its nature is discussed as based on the existing experimental data. In particular, we analyse the new data from Belle and BaBar Collaborations and argue that, while the BaBar data prefer the dynamically generated virtual state in the D\bar{D}* system, the new Belle data clearly indicate a sizable c\bar{c} 2^3P_1 component in the X wave function.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
继续探索
The BaBar Collaboration has recently reported the measurement of the ratio of the branching fractions of $\bar{B} \to D(D^{*}) τ^{-} \bar{ν_τ}$ to $\bar{B} \to D(D^{*}) \ell^{-} \bar{ν_\ell}$ which deviates from the Standard Model prediction by 2$σ$(2.7$σ$). This deviation goes up to 3.4$σ$ level when the two measurements in the $D$ and $D^*$ modes are taken together and could indicate new physics. Using an effective Lagrangian for the new physics we study the implication of these results and calculate other observables that can shed light on the nature of the new physics. We show that the mea…
We discuss possible constraints on R-parity violation from recently announced Belle/Babar results on the B\toτνbranching fraction, and the bounds on τ^-\to\ell^- K_S^0 (\ell=e or μ) from Babar.
Indications of a Four-Quark Structure for the X(3872) and X(3876) Particles from Recent Belle and BABAR Data
贝尔和巴巴尔最近的结果指出，存在第二个X粒子，衰变在D^0 D^0巴π ^0中，比X（3872）高几MeV。我们用4-夸克模型预言的中性粒子来确定这两个X态，并表明产生和衰变与这个指定是一致的。我们考虑尚未观察到的带电伙伴，并给出如何寻找它们的新提示。
Measuring the lepton anomalous magnetic moments $(g-2)$ and the rare decays of light pseudoscalar mesons into lepton pairs $P\to l^{+}l^{-} $, serve as important tests of the Standard Model. To reduce the theoretical uncertainty in the standard model predictions, the data on the charge and transition form factors of the light pseudoscalar mesons play a significant role. Recently, new data on the behavior of the transition form factors $P\toγγ* $ at large momentum transfer were supplied by the BABAR collaboration. There are several problems with the theoretical interpretation of these data: 1) …
We summarize the main features of the spectroscopy, production and decays of the $J^{PC}=1^{--}$ tetraquarks in the $b\bar{b}$ sector, concentrating on the lowest state called $Y_b(10890)$. The tetraquark framework is used to analyze the BaBar data on the $e^+ e^- \to b\bar{b}$ cross section ($R_b$ energy scan) between $\sqrt{s}= 10.54$ and 11.20 GeV and the Belle data on the processes $e^+e^- \to Υ(1S) π^+π^-,Υ(2S) π^+π^-$ near the peak of the $Υ(5S)$ resonance. The BaBar $R_b$ energy scan is consistent with an additional state at a mass of 10.90 GeV and a width of about 28 MeV, in broad agre…
Using Geant4 in the BaBar Simulation
Babar是第一个将Geant 4纳入其探测器模拟的大型实验。自2001年7月以来，使用这种模拟已经产生了15亿个巴巴尔事件。在一个典型的e+e- -> Upperment（4s）-> B 0 B 0 bar事件中，发生器会产生30到60个径迹，并通过探测器传播，使用Geant 4工具包提供的衰变，电磁和强子过程。探测器的材料模型非常详细，并开发了一个特殊的粒子传输模块，以便在传播过程中对微小特征（几微米尺度）进行采样，而不会牺牲性能。这种事件的传播阶段在866 MHz处理器上需要5 CPU秒。还将介绍其他Babar事件类型的执行速度。正在用巴巴尔数据验证模拟事件，并将显示蒙特卡罗/数据比较的结果。模拟代码的设计，如何使用Geant 4工具包，以及正在进行的努力，以提高数据和蒙特卡洛之间的协议的讨论也将提交。
At leading-twist accuracy the form factors for the transitions from a virtual photon to the $η$ or $η'$ can be expanded into a power series of the variable $ω$, being related to the difference of two photon virtualities. The series possess the remarkable feature that only the Gegenbauer coefficients of the meson distribution amplitudes of order $l\leq m$ contribute to the term $\sim ω^m$. Thus, for $ω\to 0$ only the asymptotic meson distribution amplitude contributes, allowing for a test of the mixing of the $η$ and $η'$ decay constants. Employing the Gegenbauer coefficients determined in anal…
We study the experimental $DK$ invariant mass spectra of the reactions $B^+ \to \bar{D}^0 D^0 K^+$, $B^0 \to D^- D^0 K^+$ (measured by the BaBar Collaboration) and $B_s \to π^+ \bar{D}^0 K^-$ (measured by the LHCb Collaboration), where an enhancement right above the threshold is seen. We show that this enhancement is due to the presence of $D^\ast_{s0}(2317)$, which is a $DK$ bound state in the $I(J^P) = 0(0^+)$ sector. We employ a unitarized amplitude with an interaction potential fixed by heavy meson chiral perturbation theory. We obtain a mass $M_{D^\ast_{s0}} = 2315^{+12}_{-17}\ ^{+10}_{-5…
A B-factory continuum retune of PYTHIA 8 hadronization parameters using BELLE and BABAR identified-hadron data
基于BELLE和BABAR在Υ(4S)附近的测量，对PYTHIA 8中e⁺e⁻→q\bar q过程的强子化参数进行精细调谐，通过分阶段扩展参数集，最终在20803个bin上获得73.42的加权分数，优于Skands参考和Monash 2013。
The available data on the $D\overline{D}$ and inclusive hadronic cross sections in the $ψ(3770)$ region from the BaBar, Belle, BES-II, CLEO and KEDR experiments have been analyzed assuming that systematic uncertainties on cross sections measured by different detectors are not correlated. Four theoretical models predicting the $ψ(3770)$ line shape were considered for the $D\overline{D}$ channel. All of them gave satisfactory description of the data. The combined analysis of the $D\overline{D}$ and inclusive hadronic channel was performed using the model based on the vector dominance approach an…
We expect that $BR(χ_{c2}(2P)\to gluon\, gluon)\gtrsim 2 \%$ if Particle Data Group as well as BaBar and Belle collaboration correctly identified the state. In reality, this branching ratio corresponds to the one for $χ_{c2}(2P)$ decaying to the light hadrons. We also discuss the detection possibilities of these decays.
Recently, the {\it Belle} and {\it BABAR} Collaborations published the single-inclusive electron-positron annihilation data at the center of mass energies ($\sqrt{s}$) of $10.52$ GeV and $10.54$ GeV, respectively. These new data offer one the possibility to determine the nonperturbative initial conditions of fragmentation functions much more accurately. In our previous work \cite{Soleymaninia:2013cxa}, we extracted the fragmentation functions for $π^\pm$ and $K^\pm$ particles at next-to-leading order (NLO) including these new data, for the first time. These new data are in the regions of large…
Using recently published, high-precision pi+pi- cross section data by the BABAR experiment from the analysis of e+e- events with high-energy photon radiation in the initial state, we reevaluate the lowest order hadronic contribution a_mu[had,LO] to the anomalous magnetic moment of the muon. We employ newly developed software featuring improved data interpolation and averaging, more accurate error propagation and systematic validation. With the new data, the discrepancy between the e+e- and tau-based results for the dominant two-pion mode reduces from previously 2.4 sigma to 1.5 sigma in the di…
The strong decays of the $D_{s1}(2710)$ and $D_{sJ}(2860)$ are investigated in the framework of the $^3P_0$ model. Its decay properties newly reported by the BaBar Collaboration can be reasonably accounted for in the presence of the $D_{s1}(2710)$ being a mixture of the $D_s(2 ^3S_1)$ and $D_s(1 ^3D_1)$. The orthogonal partner of the $D_{s1}(2710)$ is expected to have a mass of about $2.66\sim 2.9$ GeV in quark models and a width of about $40\sim 60$ MeV in the $^3P_0$ model. The predicted decay properties turn out to be consistent with the BaBar's new data in both the orthogonal partner of th…
Testing the Nature of the D_{sJ}^*(2317)^+ and D_{sJ}(2463)^+ States Using Radiative Transitions
Babar和CLEO合作组最近观测到的态分别衰减到D_s^+π^0和D_s^{*+}π^0，并提出了一种可能的解释，即它们是P波c \bar{s}态的缺失，J^P=0^+和1^+。在本说明中，我们将D_{sJ} ^*（2317）^+和D_{sJ}（2463）^+态的性质与c \bar{s} D_{s0} ^* 和D_{s1}态的预期性质进行比较。我们预期具有报道质量的D_{s0} ^* 和D_{s1}极窄，即\sim ^* 和D_{s1}的D ^*_sγ和D ^*_s γ具有较大的分支比。对巴巴尔和CLEO观测结果的解释至关重要的是辐射跃迁的测量。我们注意到，在向$D_s^*$的辐射跃迁中可能观察到$D_{s1}(2536)$。
The hadronic current for the $τ^- \to π^-π^+π^-ν_τ$ decay calculated in the framework of the Resonance Chiral Theory with an additional modification to include the $σ$ meson is described. Implementation into the Monte Carlo generator Tauola and fitting strategy to get the model parameters using the one-dimensional distributions are discussed. The results of the fit to one-dimensional mass invariant spectrum of the BaBar data are presented.
The new BABAR data on the pion-photon transition form factor arouses people's new interests on the determination of pion distribution amplitude. To explain the data, we take both the leading valence quark state's and the non-valence quark states' contributions into consideration, where the valence quark part up to next-to-leading order is presented and the non-valence quark part is estimated by a phenomenological model based on its limiting behavior at both $Q^2\to 0$ and $Q^2\to\infty$. Our results show that to be consistent with the new BABAR data at large $Q^2$ region, a broader other than …
We present a unified analysis of the decays of bottomonia Upsilon(mS) -> Upsilon(nS) pi pi (m>n, m=2,3,4,5, n=1,2,3), charmonia J/psi -> phi (pi pi, K antiK), psi(2S) -> J/psi pi pi and the isoscalar S-wave processes pi pi -> pi pi, K antiK, eta eta. In this analysis we extend our recent study of low-lying (m=2,3) radial excitations of bottomonia to modes involving higher (m=4,5) excited states. Similarly as for the data on lower radial excitations, we confirm that the data for higher radially excited states from the BaBar and Belle collaborations can be described under conditions that the fin…
Recently, the BABAR collaboration published (arXiv:0905.4778) data for the photon-pion transition form factor $F_{πγγ^{\ast}}(Q^{2})$, which are in strong contradiction to the predictions of the standard factorization approach to perturbative QCD. Immediately afterwards, two mechanisms were suggested (A.E. Dorokhov, arXiv:0905.4577; A.V. Radyushkin, arXiv:0906.0323), that logarithmically enhance the form factor asymptotics and therefore provide a qualitatively satisfactory description of the BABAR data. However, the physics of the BABAR effect was not fully clarified. In the present work, base…
We present an extended analysis of the data for the pion-photon transition form factor from different experiments, CELLO, CLEO, and BaBar, and discuss various theoretical approaches which try to reason from them. We focus on the divergent behavior of the BaBar data for the pion and those for the $η(η')$ pseudoscalar mesons and comment on recently proposed explanations for this discrepancy. We argue that it is not possible at present to accommodate these data within the standard QCD framework self-consistently.
Gluonic charmonium resonances at BaBar and Belle?
我们面临的预测混合粲和其他胶子激发的魅力区域最近观察到的结构在3 GeV以上的质量范围。Y（4260），如果共振，被发现同意与预期的混合charmonium。其他胶子激发的可能性，可能会影响该地区的数据进行了讨论。
New BaBar studies of high-order radiation and the new landscape of data-driven HVP predictions of the muon g-2
本文利用BaBar数据首次测量次领头阶和次次领头阶额外辐射，发现与生成器预测的差异，并评估其对KLOE和BESIII的影响，为μ子g-2偏差提供新见解。
The pion-photon transition form factor (TFF) provides strong constraints on the pion distribution amplitude (DA). We perform an analysis of all existing data (CELLO, CLEO, BaBar, Belle) on the pion-photon TFF by means of light-cone pQCD approach in which we include the next-to-leading order correction to the valence-quark contribution and estimate the non-valence-quark contribution by a phenomenological model based on the TFF's limiting behavior at both $Q^2\to 0$ and $Q^2\to\infty$. At present, the pion DA is not definitely determined, it is helpful to have a pion DA model that can mimic all …
A state-of-the-art analysis of the pion-photon transition form factor is presented based on an improved theoretical calculation that includes the effect of a finite virtuality of the quasi-real photon in the method of light-cone sum rules. We carry out a detailed statistical analysis of the existing experimental data using this method and by employing pion distribution amplitudes with up to three Gegenbauer coefficients $a_2, a_4, a_6$. Allowing for an error range in the coefficient $a_6\approx 0$, the theoretical predictions for $γ^*γ\toπ^0$ obtained with nonlocal QCD sum rules are found to b…
Using a full BABAR data sample of 426 $fb^{-1}$, we present improved measurements of the ratio ${\cal{R}}(D^{(*)}) = {\cal{B}} (\bar{B} \to D^{(*)}τ^{-}\barν_τ)/$ ${\cal{B}} (\bar{B} \to D^{(*)}\ell_{\ell}^{-}\barν_{\ell})$, where $\ell$ is either electron or muon. We measure ${\cal{R}}(D) = 0.440 \pm 0.058 \pm 0.042$ and ${\cal{R}}(D^*) = 0.332 \pm 0.024 \pm 0.018$. These ratios exceed the Standard Model predictions by $2.0σ$ and $2.7σ$, respectively. The results disagree with the Standard Model predictions at the level of $3.4σ$. The ratios are sensitive to new physics contributions in the f…
We present searches for rare charm decays of the form $X_c^+ \to h^{\pm} \ell^{\mp} \ell^{(')^+}$, where $X_c^+$ is a charm hadron either $D^+$, $D_s^+$, or $Λ_c^+$, and $\ell^{(')^{\pm}}$ is an electron or muon. These modes are based on 384 $fb^{-1}$ of $e^+ e^-$ annihilation data collected at the $Υ(4S)$ resonance with the BABAR detector at the SLAC National Accelerator Laboratory. We also present the flavor-changing neutral-current decays $D^0 \to e^+e^-$, $D^0 \to μ^+ μ^-$, and $D^0 \to e^{\pm} μ^{\mp}$ that corresponds to an integrated luminosity of 468 $fb^{-1}$ of data. The decay $D^0 \…
The new data on the $γ^*γ\to π^0$ transition form factor of the Belle Collaboration are analyzed in comparison with those of BaBar (including the older data of CELLO and CLEO) using an approach based on light-cone sum rules. Performing a 2-, and a 3-parametric fit to these data, we found that the Belle and the BaBar data have no overlap at the $1σ$ level. While the Belle data agree with our predictions, the Babar data are in conflict with them.
The $ρ$ meson magnetic dipole moment from BaBar $e^+e^- \to π^+ π^-π^0 π^0 $ cross section measurement
本研究利用BaBar合作组的$e^+e^-$湮灭到四π过程数据，结合矢量介子主导模型提取$ρ$介子磁偶极矩，通过更可靠的数据与方法改进了此前的测量结果。
扫码添加微信好友，提出您的宝贵建议 👇
💡 备注请填写：网站反馈
发表机构由 AI 从论文文本抽取，如发现错误，欢迎反馈修正建议。