The Decay B --> K l^+ l^- at Low Hadronic Recoil and Model-Independent Delta B = 1 Constraints
Christoph Bobeth, Gudrun Hiller, Danny van Dyk, Christian Wacker
备注：
23 pages, 11 figures; v2: Treatment of experimental uncertainties in likelihood-function in EOS fixed and constraints from scan on C_9, C_10 updated (Figs 5, 6, 7, 8 and Eqs 3.1, 3.2, 3.5 and 3.6). Main results and conclusions unchanged
We study the decay B --> K l^+ l^- for l = e,mu,tau with a softly recoiling kaon, that is, for high dilepton invariant masses sqrt{q^2} of the order of the b-quark mass. This kinematic region can be treated within an operator product expansion and simplified using heavy quark symmetry, leading to systematic predictions for heavy-to-light processes such as B --> K^(*) l^+ l^-. We show that the decay rates of both B --> K^* l^+ l^- and B --> K l^+ l^- decays into light leptons depend on a common combination of short-distance coefficients. The corresponding CP-asymmetries are hence identical. Furthermore we present low recoil predictions for B --> K l^+ l^- observables, including the flat term in the angular distribution which becomes sizable for taus. We work out model-independently the constraints on Delta B = 1 operators using the most recent data from the experiments BaBar, Belle, CDF and LHCb. For constructive interference with the standard model, generic new physics is pushed up to scales above 44 TeV at 95% CL. Assuming none or small CP-violation we obtain a lower bound on the position of the zero of the forward-backward asymmetry of B^0 --> K^*0 l^+ l^- decays as q_0^2 > 1.7 GeV^2, which improves to q_0^2 > 2.6 GeV^2 for a standard model-like sign b --> s gamma amplitude.
$B \to K \ell^{+}\ell^{-}$ decay at large hadronic recoil
我们预测的振幅的$B\to K \ell^+\ell^-$衰变的区域的双轻子不变质量平方$0<q^2\leq m_{J/ψ}^2$，即在大强子反冲。从QCD光锥求和规则得到了进入衰变振幅可因子分解部分的$B\to K$形状因子。在$q^2<0$中计算了由四夸克和企鹅算符结合电磁相互作用产生的非定域效应，远低于强子阈值。对于硬胶子贡献，我们采用QCD因子分解方法。软胶子不可因式分解的贡献由QCD光锥求和规则估计。计算结果与变量$q^2$中的强子色散关系相匹配，然后继续到衰变的运动学区域。在强反冲作用下，$B\to K\ell^+\ell^-$的非定域贡献的总体效应是中等的。预测的$B\to K \ell^+\ell^-$部分宽度的主要不确定性由$B\to K$形状因子引起。此外，在这种衰变中的同位旋不对称性预计是非常小的。我们通过引入一个新的物理贡献的有效哈密顿量，研究了观测量从标准模型预测的偏差。
We provide hadronic input for the $B$-meson semileptonic transitions to a light pseudoscalar meson at large recoil. The $B_s\to K$ form factor calculated from QCD light-cone sum rule is updated, to be used for a $|V_{ub}|$ determination from the $B_s\to K \ell ν$ width. Furthermore, we calculate the hadronic input for the binned observables of $B \to π\ell^+ \ell^-$ and $B \to K \ell^+ \ell^-$. In addition to the form factors, the nonlocal hadronic matrix elements are obtained, combining QCD factorization and light-cone sum rules with hadronic dispersion relations. We emphasize that, due to no…
我们考虑了τ-> 3 pi nu_ tau和4 pi nu_ tau（Δ S = 0）以及τ-> K pi pi nu_tau（Δ S = 1）中的CP破坏效应，假设这些过程的通常标准模型振幅干扰了带电希格斯玻色子介导的类似振幅。在Delta S = 0的情况下，我们特别关注中间共振过程tau -> V pi nu_tau（V=omega，rho和a_1），并考虑三个CP-奇数观测值-部分速率不对称性，偏振相关不对称性和三重产物不对称性。在Delta S = 1的情况下，我们研究部分利率不对称，两个“修改”利率不对称，和三重产品不对称。预计Delta S = 0和Delta S = 1情况下的部分速率不对称性较小。对其他不对称性的评估表明，它们可能是可以测量的。
We analyze the angular distributions of B -> K^* (-> K pi) l^+ l^- and B -> K l^+ l^- decays in the region of low hadronic recoil in a model-independent way by taking into account the complete set of dimension-six operators [sbar Gamma b][lbar Gamma' l]. We obtain several novel low-recoil observables with high sensitivity to non-standard-model Dirac structures, including CP-asymmetries which do not require flavor tagging. The transversity observables H_T^(1,3,4,5) are found to be insensitive to hadronic matrix elements and their uncertainties even when considering the complete set of operators…
We analyse $B\to K^\ast \ell\ell$ decays in the region of low hadronic recoil, where an operator product expansion (OPE) in $1/m_b$ applies. Using a local model for charm contributions based on $e^+ e^- \to hadrons$ against the OPE provides a data-driven method to access the limitations to the OPE's accuracy related to binnings in the dilepton mass. Model-independent fits to $B\to K^\ast μμ$ low recoil angular observables exhibit presently only small sensitivity to different charm models. They give similar results as the fits based on the OPE, and are in agreement with the standard model, but …
Searches for new hadronic resonances typically focus on high-mass spectra, due to overwhelming QCD backgrounds and detector trigger rates. We present a study of searches for relatively low-mass hadronic resonances at the LHC in the case that the resonance is boosted by recoiling against a well-measured high-$p_{\textrm{T}}$ probe such as a muon, photon or jet. The hadronic decay of the resonance is then reconstructed either as a single large-radius jet or as a resolved pair of standard narrow-radius jets, balanced in transverse momentum to the probe. We show that the existing 2015 LHC dataset …
Hadronic vacuum polarization in hydrogen-like atoms and ions amid the interplay of recoil and finite-size effects
Institut für Kernphysik and PRISMA ++ Cluster of Excellence, Johannes Gutenberg-Universität Mainz（美因茨约翰内斯·古腾堡大学核物理研究所与PRISMA++卓越集群）；LPNHE, Sorbonne Université, Université Paris Cité, CNRS/IN2P3（巴黎萨克雷大学、巴黎西岱大学及法国国家科学研究中心/欧洲核子研究组织高能物理实验室）
我们研究了Delta S=0衰变tau -> omega pi nu_tau和tau -> a_1 pi nu_tau以及Delta S=1衰变tau -> K pi pi nu_tau中的CP破坏。我们假设新的物理是带电的希格斯粒子。我们发现，相当大的CP违反的影响是可能的，在tau -> a_1 π nu_tau（偏振相关的速率不对称性）和tau -> omega π nu_ tau（三重产品不对称性）。Δ S=1衰减τ-> K pi pi nu_tau可以通过几个共振进行。我们构建了两个修改后的速率不对称性和三重产品不对称性，这种衰变，并讨论这些不对称性的潜在敏感性。
Tracing Gluon Saturation through Hadronization at EIC
Central China Normal University（华中师范大学）；Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所）；Shandong University（山东大学）；École Polytechnique, Institut Polytechnique de Paris（巴黎理工学院巴黎综合理工学校）
The Unitarity Triangle Fit in the Standard Model and Hadronic Parameters from Lattice QCD: A Reappraisal after the Measurements of Delta m_s and BR(B to tau nu)
Combining exclusive semi-leptonic and hadronic B decays to measure |V_ub|
Cabibbo-Kobayashi-Maskawa矩阵元|V_ub|可以从半轻子衰变B -> pi +1+反中微子_1的速率中提取出来，只要B -> pi跃迁的强子形状因子可以从其他B衰变中测量出来，理论上的不确定性很小。在这里，我们建议使用衰变B -> π J π。这是一个颜色抑制衰减，它不能正确地描述在通常的因式分解近似，我们使用一个简单的和非常普遍的现象学模型的b d J顶点。为了联系B -> pi J衰变和B -> pi + l +反中微子_l衰变中的强子形状因子，我们使用了在大反冲时重-轻跃迁的形状因子关系。
We study the differential decay rate for the rare $Λ_b \to Λ(\to N π)\ell^+\ell^-$ transition, including a determination of the complete angular distribution, assuming unpolarized $Λ_b$ baryons. On the basis of a properly chosen parametrization of the various helicity amplitudes, we provide expressions for the angular observables within the Standard Model and a subset of new physics models with chirality-flipped operators. Hadronic effects at low recoil are estimated by combining information from lattice QCD with (improved) form-factor relations in Heavy Quark Effective Theory. Our estimates f…
In this paper we discuss the Standard Model and new physics sensitivity of the $Λ_b\toΛ^\ast(1520)(\to N\!\bar{K})\ell^+\ell^-$ decay at low-recoil, where $\ell^\pm$ are massive leptons and $N\!\bar{K}=\{pK^-, n\bar{K}^0 \}$. We provide a full angular distribution with a set of operators that includes the Standard Model operators and their chirality flipped counterparts, and new scalar and pseudo-scalar operators. The resulting angular distribution allows us to construct observables that we study in the Standard Model and in model-independent new physics scenarios. To reduce the hadronic effec…
We present an effective field theory of the $Δ$-resonance as an interacting Weinberg's $(3/2,0)\oplus (0,3/2)$ field in the multi-spinor formalism. We derive its interactions with nucleons $N$, pions $π$ and photons $γ$, and compute the $Δ$-resonance cross-sections in pion-nucleon scattering and pion photo-production. The theory contains only the physical spin-3/2 degrees of freedom. Thus, it is intrinsically consistent at the Hamiltonian level and, unlike the commonly used Rarita-Schwinger framework, does not require any additional ad hoc manipulation of couplings or propagators. The symmetri…
We critically reassess the theoretical uncertainties in the Standard Model calculation of the $B \to K^* \ell^+ \ell^-$ observables, focusing on the low $q^2$ region. We point out that even optimized observables are affected by sizable uncertainties, since hadronic contributions generated by current-current operators with charm are difficult to estimate, especially for $q^2 \sim 4 m_c^2\simeq 6.8$ GeV$^2$. We perform a detailed numerical analysis and present both predictions and results from the fit obtained using most recent data. We find that non-factorizable power corrections of the expecte…
We study the differential decay rate for the rare decay $Λ_b\to Λ(1520)(\to NK)\ell^+\ell^-$ where $\ell$ is a light lepton, as this decay mode can provide new and complementary constraints on the Wilson coefficients in $b\to s\ell^+\ell^-$ transitions compared to other modes. We provide a determination of the complete angular distribution, assuming unpolarised $Λ_b$ baryons and neglecting the lepton mass. The resulting angular observables are expressed in terms of helicity amplitudes involving hadronic form factors within the Standard Model and New physics models with chirality-flipped operat…
We have investigated the effect of nucleon and delta resonances with spins 11/2, 13/2, and 15/2 in the kaon photoproduction process $γ+ N \to K + Y$ by using two covariant isobar models. The formalism for high-spin propagators and interaction Lagrangians were adopted from the works of Pascalutsa and Vrancx et al. The unknown parameters in the amplitudes, i.e., the coupling constants and hadronic form factor cutoffs, were obtained by fitting the calculated observables to experimental data. In the $KΛ$ channels the inclusion of $N(2600)I_{1,11}$ and $N(2700)K_{1,13}$ resonances improves the agre…
