The LHC physics era is about to commence; here we discuss a complementary physics program that would be realized at a high luminosity flavor factory. A flavor factory experiment can search for new physics in CP asymmetries, inclusive decay processes, rare leptonic processes, absolute branching fractions, and other measurements that are challenging or not feasible at the LHC. Such measurements would provide good sensitivity to new physics phases, the presence of a charged Higgs, and supersymmetric couplings. The charged Higgs mass range probed is similar to that accessible at the LHC.
We discuss how the intensity and the energy frontiers provide complementary constraints within a minimal model of neutrino mass involving just one new field beyond the Standard Model at accessible energy, namely a doubly charged scalar $S^{++}$ and its antiparticle $S^{--}$. In particular we focus on the complementarity between high-energy LHC searches and low-energy probes such as lepton flavor violation. Our setting is a prime example of how high- and low-energy physics can cross-fertilize each other.
The simplest realization of the inverse seesaw mechanism in a $SU(3)_C \otimes SU(3)_L \otimes U(1)_X$ gauge theory offers striking flavor correlations between rare charged lepton flavor violating decays and the measured neutrino oscillations parameters. The predictions follow from the gauge structure itself without the need for any flavor symmetry. Such tight complementarity between charged lepton flavor violation and oscillations renders the scenario strictly testable.
The LHC has not discovered any New Physics beyond the anticipated $h(125)$ boson, and new ideas abound for out-of-the-box searches, or Effective Field Theories with multi-TeV cutoff. But, have we exhausted dimension-4 operators involving sub-TeV particles that are {\it not} exotic (non-XLP)? We advocate the existence of an extra Higgs doublet that carry extra Weinberg couplings, where {\it emergent} mass-mixing hierarchies {\it and} alignment have hidden their effects very well so far. ${\cal O}(1)$ Higgs quartics can induce first order electroweak phase transition and imply sub-TeV $H, A, H^\…
Although searches for new physics at the CERN Large Hadron Collider will probably dominate the the agenda of the experimental high energy physics community during the next decade or more, high-intensity experiments at the tau-charm and beauty thresholds will continue to play important complementary roles. These include the establishment of stringent constraints on proposed theories for beyond-the-Standard-Model physics and unique opportunities to address some new physics scenarios that are inaccessible at the LHC. In addition, in the event that the LHC does discover some new phenomena, high se…
We examine the low-energy signatures of axion-like particles (ALPs) in lepton flavor violating (LFV) processes. By using a dimension-5 effective Lagrangian, we compute the most general ALP contributions to LFV decays of leptons and mesons. The provided expressions are valid for any choice of ALP mass and couplings. We explore the complementarity of different processes, identifying specific patterns to be experimentally tested. Constraints on LFV couplings are derived from existing data and prospects for forthcoming experiments are also discussed. As a by-product, we revisit the possibility of …
随着在$Υ(4S)$共振运行的非对称$e^+ e^-$对撞机（“B工厂”）上进行的第一代实验接近完成，一个高光度机器的新时代即将到来。我们在这里报告的计划，在KEK在日本的升级KEKB机（“SuperKEKB”）的目标是实现瞬时亮度超过$8 \times 10^{35}$ cm $^{-2}$ s $^{-1}$，这几乎是两个数量级高于KEKB。与机器一起，Belle探测器也将升级（“Belle-II”），并进行重大改进，以提高其背景容限并改善其物理性能。新一代实验计划于2013年获得第一批数据。
Starting from a general effective Lagrangian for lepton flavor violation (LFV) in quark-lepton transitions, we derive constraints on the effective coefficients from the high-mass tails of the dilepton processes $pp \to \ell_k \ell_l$ (with $k\neq l$). The current (projected) limits derived in this paper from LHC data with $36~\mathrm{fb}^{-1}$ ($3~\mathrm{ab}^{-1}$) can be applied to generic new physics scenarios, including the ones with scalar, vector and tensor effective operators. For purely left-handed operators, we explicitly compare these LHC constraints with the ones derived from flavor…
Interactions that manifest themselves as lepton number violating processes at low energies in combination with sphaleron transitions typically erase any preexisting baryon asymmetry of the Universe. In this article, we discuss the constraints obtained from an observation of neutrinoless double beta decay in this context. If a new physics mechanism of neutrinoless double beta decay other than the standard light neutrino exchange is observed, typical scenarios of high-scale baryogenesis will be excluded unless the baryon asymmetry is stabilized via some new mechanism. We also sketch how this con…
Top-quark physics has entered the precision era. In this talk we discuss the theoretical ingredients required for a global approach to the complete set of top-quark couplings at NLO accuracy. In particular, recent developments on top-quark flavor-changing neutral couplings are shown as an example. Aspects of flavor-conserving sector will also be discussed.
Exploring $Z/γ$-mediated heavy FCNCs at the FCC-ee
Indian Institute of Technology Guwahati（印度理工学院古瓦哈提分校）；Shanghai Institute for Advanced Studies（上海高等研究院）；University of Science and Technology of China（中国科学技术大学）
A modest extension of the Standard Model by two additional Higgs doublets - the Higgs Troika Model - can provide a well-motivated scenario for successful baryogenesis if neutrinos are Dirac fermions. Adapting the "Spontaneous Flavor Violation" framework, we consider a version of the Troika model where light quarks have significant couplings to the new multi-TeV Higgs states. Resonant production of new scalars leading to di-jet or top-pair signals are typical predictions of this setup. The initial and final state quarks relevant to the collider phenomenology also play a key role in baryogenesis…
The last decade was remarkable for neutrino physics. In particular, the phenomenon of neutrino flavor oscillations has been firmly established by a series of independent measurements. All parameters of the neutrino mixing are now known and we have elements to plan a judicious exploration of new scenarios that are opened by these recent advances. With precise measurements, we can test the 3-neutrino paradigm, neutrino mass hierarchy and CP asymmetry in the lepton sector. The future long-baseline experiments are considered to be a fundamental tool to deepen our knowledge of electroweak interacti…
