One of the exciting results in flavor physics in recent times is the $R_D$/$R_{D^*}$ puzzle. The measurements of these flavor ratios performed by the B-factory experiments, BaBar and Belle, and the LHCb experiment are about $4σ$ away from the Standard Model expectation. These measurements indicate that the mechanism of $b\rightarrow cτ\barν$ decay is not identical to that of $b\rightarrow c(μ/e)\barν$. This charge lepton universality violation is particularly intriguing because these decays occur at tree level in the Standard Model. In particular, we expect a moderately large new physics contribution to $b\rightarrow cτ\barν$. The different types of new physics amplitudes, which can explain the $R_D$/$R_{D^*}$ puzzle, have been identified previously. In this letter, we show that the polarization fractions of $τ$ and $D^*$ and the angular asymmetries $A_{FB}$ and $A_{LT}$ in $B\rightarrow D^*τ\barν$ decay have the capability to uniquely identify the Lorentz structure of the new physics. A measurement of these four observables will lead to such an identification.
Non-leptonic $B^0_s \rightarrow D_s^{\pm} K^{\mp}$ transitions are particularly interesting processes to test the Standard Model. As these decays occur via pure tree diagrams, they allow a theoretically clean determination of the angle $γ$ of the unitarity triangle. Considering recent LHCb results, an intriguing picture arises, showing tension with the Standard Model. Extracting the branching ratios of the underlying $\bar{B}^0_s \rightarrow D_s^{\pm} K^{\mp}$ modes and combining them with information from semileptonic $B_{(s)}$ decays, we arrive at another puzzling situation, in accordance wi…
Anomalies in semi-leptonic $B$ decays could indicate new physics beyond the standard model(SM). There is an older puzzle in non-leptonic $B \to πK$ decays. The new particles, leptoquarks and diquarks, required to solve the semi-leptonic and the non-leptonic puzzles can also generate neutrino masses and mixing at loop level. We show that a consistent framework to explain the $B$ anomalies and the neutrino masses is possible and we make predictions for certain rare nonleptonic $B$ decays.
We study the non-leptonic puzzle of $B_{d(s)} \rightarrow K^{(\ast)}\bar{K}^{(\ast)}$ decay in the $R$-parity violating minimal supersymmetric standard model (RPV-MSSM) extended with the inverse seesaw mechanism. In this model, the chiral flip of sneutrinos can contribute to the observables $L_{K\bar{K}}$ and $L_{K^{\ast}\bar{K}^{\ast}}$, that is benefit for explaining the relevant puzzle. We also find that this unique effect can engage in the $B_s$-$\bar{B}_s$ mixing. We utilize the scenario of complex $λ^\prime$ couplings to fulfill the recent stringent constraint of $B_s$-$\bar{B}_s$ mixing…
The next-to-next-to-leading order (NNLO) pQCD prediction for the $γγ^* \to η_c$ form factor was evaluated in 2015 using nonrelativistic QCD (NRQCD). A strong discrepancy between the NRQCD prediction and the BaBar measurements was observed. Until now there has been no solution for this puzzle. In this paper, we present a NNLO analysis by applying the Principle of Maximum Conformality (PMC) to set the renormalization scale. By carefully dealing with the light-by-light diagrams at the NNLO level, the resulting high precision PMC prediction agrees with the BaBar measurements within errors, and the…
The decays of $η$ and $η^\prime$ mesons provide unique opportunities for testing the properties of low energy Quantum Chromodynamics and for the search of new physics beyond the Standard Model. However, recent experimental results on the rare decays of $η^{\left(\prime\right)}\rightarrowπ^0\left(η\right)γγ$ cannot be self-consistently described by the combination of the Vector Meson Dominance and Linear Sigma Model employing the same set of parameters. We show that this tension can be attributed to the presence of a leptophobic dark photon $\mathcal{B}$, and find representative values of the p…
Pauli blocking and entanglement solve $Kπ$ puzzle. CP violation in $B^o \rightarrow Kπ$; not in $B^{\pm} \rightarrow Kπ$decays
新的数据分析与泡利阻塞和纠缠解释了CP破坏在$B^o\rightarrow Kπ$衰变，在$B^{\pm} \rightarrow Kπ$衰变的缺席，并预测了意想不到的对比纯I=1/2在个人$B^{\pm}$和$B^o$最终状态和I=1/2违反之间的关系。对$B\rightarrow Kπ$数据的分析预测了这些观察到的同位旋关系，并解释了对旁观者夸克味的依赖。$B^+ \rightarrow Kπ$树形图$\bar b u\rightarrow \bar s u \bar u u$有两个相同的$u$夸克，分别来自弱顶点夸克和旁观者夸克。泡利原理要求这些短距离的夸克具有色或自旋反对称的波函数。守恒对称性的本征值在两个分离介子的终态中保持纠缠。这种泡利纠缠抑制了$B^+$衰变中的树企鹅干涉和CP破坏，但在有旁观者$d$夸克的$B^o$衰变中没有。即使在角动量为零的电荷共轭下，四体波函数也必须有两个对称性相同的反夸克与两个u夸克结合，才能碎裂成两个赝标介子态。它属于味SU（3）的27维表示，其中$ππ$态的同位旋I=2，相应的奇异态的V自旋V=2，奇异态是$Kπ$和$Kη_8$的线性组合。这些对称性即使在分离成两个介子后仍然纠缠在四体波函数中。强泡利抑制树过渡到$Kπ$只有一个小的V=2的分量，主要是V=1。没有泡利抑制过渡到I=2 $ππ$状态也有两个$u$夸克，但不同的颜色自旋耦合。…
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.
Particularly interesting processes to test the Standard Model are non-leptonic $B^0_s \rightarrow D_s^{\pm} K^{\mp}$ transitions. As these decays occur via pure tree diagrams, they allow a theoretically clean determination of the angle $γ$ of the unitarity triangle. Considering recent LHCb results, an intriguing picture arises, showing tension with the Standard Model. Utilising the available experimental data, we perform a theoretical analysis in order to shed more light on these puzzling patterns. Do these puzzles actually indicate footprints of New Physics?
New insights into the $b\rightarrow c \bar{u}q$ puzzle through Top-Bottom synergies
University College London（伦敦大学学院）；City St. George’s, University of London（伦敦大学圣乔治城市学院）；University of Manchester（曼彻斯特大学）；Durham University（杜伦大学）；Universität Siegen（锡根大学）
研究通过顶-底协同性探讨$b\ ightarrow c \bar{u}q$异常，分析强耦合新物理对碰撞实验的影响，发现即使增加$t\ar{t}$衰变分支比，弱双态标量的限制仍强，且QCD因子化可能因高次修正而破裂。
We propose that three recent anomalies in $B$ meson decays, $R_{D^{(*)}}$, $R_K$, and $P_5'$, might be explained by a single vector leptoquark weak triplet state. The constraints on the parameter space are obtained by considering $t \to b τ^+ ν$ data, lepton flavor universality tests in the kaon sector, bounds on $B \to K^{(*)} \bar νν$, bound on the lepton flavor violating decay $B \to K μτ$, and measurements of $b \to c μ^- \barν$ decays. The presence of such vector leptoquark could be exposed in precise measurements of $t \to b τν$ and $B \to K^{(*)} \bar νν$ decays. The model also predicts…
Discrepancies from in-beam and in-bottle type experiments measuring the neutron lifetime are on the 4$σ$ standard deviation level. In a recent publication Fornal and Grinstein proposed that the puzzle could be solved if the neutron would decay on the one percent level via a dark decay mode, one possible branch being $n \rightarrow χ+ e^+ e^-$. With data from the \perkeoII experiment we set limits on the branching fraction and exclude a one percent contribution for $95\,\%$ of the allowed mass range for the dark matter particle.
High-mass twins & resolution of the reconfinement, masquerade and hyperon puzzles of compact star interiors
我们的目标是有助于解决与致密星致密核结构（CS）有关的三个基本难题：（i）超子难题：如何协调$2\,$ M $_\odot$的脉冲星质量与超子软化状态方程（EoS）;（ii）伪装问题：现代EOS冷，高密度强子和夸克物质几乎是相同的;（iii）的refinement难题：怎么办时，解除禁闭过渡后的强子EOS再次成为有利的？我们表明，考虑到重子的复合性（排除体积和/或夸克泡利阻塞）的强子侧和夸克物质侧的限制和硬化效应的结果在早期的相变到夸克物质，在高密度，消除了所有三个目前的CS内部的困惑。此外，在这类新的EoS的混合CS下降的一个有趣的情况下，一个强的一阶相变，导致可观察到的高质量的双星现象，天体物理观测的一个关键端点的QCD相图。
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…
The long-standing puzzle of the quenched $g_A$ in nuclei -- and in dense matter -- is shown to have a simple resolution in a scale-symmetric HLS chiral Lagrangian at the Fermi-liquid fixed point. This resolution exposes scale-chiral symmetry, hidden in QCD in the vacuum, emerging in nuclear matter from low density to high compact-star density. It has important implications on "first principles" approaches to nuclear physics, such as the role of multi-body exchange currents in Gamow-Teller matrix elements in nuclei and in neutrinoless double $β$ decays for going Beyond the Standard Model.
The recently developed hadron resonance gas model with multicomponent hard-core repulsion is used to address and resolve the long standing problem to describe the light nuclear cluster multiplicities including the hyper-triton measured by the STAR Collaboration, known as the hyper-triton chemical freeze-out puzzle. An unprecedentedly accurate description is obtained for the hadronic and other light nuclear cluster data measured by STAR at the collision energy $\sqrt{s_{NN}} =200$ GeV and by ALICE at $\sqrt{s_{NN}} =2.76$ TeV. This success is achieved by applying the new strategy of analyzing t…
Astrophysics today faces a number of mysteries which defiant their resolutions in spite of drastic improvements in instrumental design, better technique being developed, and gradual improvements in theoretical and computation methods over last decades. Primordial Lithium Puzzle is known to stay with us for at least two decades, and it is very likely that its final resolution will require some fundamentally new ideas, novel frameworks and a non-conventional paradigms. We propose that Primordial Lithium Puzzle finds its natural resolution within the so-called Axion Quark Nugget (AQN) dark matter…
We present a summary of the recent results obtained with the novel hadron resonance gas model with the multicomponent hard-core repulsion which is extended to describe the mixtures of hadrons and light (anti-, hyper-)nuclei. A very accurate description is obtained for the hadronic and the light nuclei data measured by STAR at the collision energy $\sqrt{s_{NN}} =200$ GeV and by ALICE at $\sqrt{s_{NN}} =2.76$ TeV. The most striking result discussed here is that for the most probable chemical freeze-out scenario for the STAR energy the found parameters allow us to reproduce the values of the exp…
Addressing the $R_{τ/{μ,e}}\left(D^{(*)}\right)$ puzzle through New Physics four-fermion operators and their impact on $Λ_{b}\rightarrowΛ_{c}τ\barν_τ$ decay
We describe DSiD, a fast simulation Delphes detector for the International Linear Collider (ILC) based on the full simulation performance of the SiD detector. SiD is one of two detectors described in the ILC Technical Design Report (TDR). The tracking efficiency, tracking momentum resolution, electromagnetic and hadronic calorimeter energy resolution, particle identification and flavor tagging efficiencies are taken from the Detailed Baseline Design (DBD) study as described in ILC TDR Volume 4: Detectors. In a cross-check study with $4 \times 10^6$ $e^+ e^- \rightarrow b \bar{b}$ events genera…
We investigate the four-body decays $B_{(s)} \rightarrow (Kπ)_{S/P} (Kπ)_{S/P}$ in the $Kπ$-pair invariant mass region around the $K^*(892)$ resonance in the perturbative QCD (PQCD) approach, where $(Kπ)_{S/P}$ denotes a $S$- or $P$-wave $Kπ$ configuration. The contributions from the $P$-wave resonance $K^*(892)$ and from possible $S$-wave components are included into the parametrization of the $Kπ$ two-meson distribution amplitudes, which are the nonperturbative inputs in this formalism. We calculate the branching ratio for each resonance and observe sizable $S$-wave contributions to the $B_s…
The universality of the weak interactions can be tested in semileptonic $b \to c$ transitions, and in particular in the ratios $R(D^{(*)}) \equiv Γ(B \rightarrow D^{(*)} τν)/Γ(B \rightarrow D^{(*)} \ell ν)$ (where $\ell = μ$ or $e$). Due to the recent differences between the experimental measurements of these observables by BaBar, Belle and LHCb on the one hand and the Standard Model predicted values on the other hand, we study the predicted ratios $R(D^{(*)}) = Γ(B \rightarrow D^{(*)} τ+$ "missing" $)/Γ(B \rightarrow D^{(*)} \ell ν)$ in scenarios with an additional sterile heavy neutrino of m…
UV Luminosity Functions from HST and JWST: A Possible Resolution to the High-Redshift Galaxy Abundance Puzzle and Implications for Cosmic Strings
McGill University（麦吉尔大学）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）；Cosmic Frontier Center, The University of Texas at Austin（德克萨斯大学奥斯汀分校宇宙前沿中心）；Massachusetts Institute of Technology（麻省理工学院）；Center for Theoretical Physics, A Leinweber Institute, Massachusetts Institute of Technology（麻省理工学院莱因韦伯理论物理中心）
