Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new user${}^8$Be Decay Anomaly and Light $Z$
58
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
In this proceedings, we discuss a light (17 MeV) $Z$ solution to the anomaly observed in the decay of Beryllium-8 by the Atomki collaboration. We detail an anomaly free model with minimal particle content which can satisfy all other experimental constraints with gauge couplings $mathcal{O}(10^{-4})$.
rate research
Read More
We have witnessed the beginning of an era where dark matter and neutrino detectors can probe similar new physics phenomena. Motivated by the low-energy electron recoil spectrum observed by the dark matter experiment, XENON1T, at Gran Sasso laboratory, we interpret the observed signal not in terms of a dark matter particle, but rather in the context of a new light $Z^prime$ gauge boson. We discuss how such a light $Z^prime$ rises in a Two Higgs Doublet Model augmented by an abelian gauge symmetry where neutrino masses and the flavor problem are addressed, in agreement with neutrino-electron scattering data.
The anomalously large experimentally measured ratios of the semitauonic decay $Brightarrow D^{(*)} +tau+ u$ and the corresponding semileptonic $Brightarrow D^{*} +l+bar{ u}_l$ disagree with the predictions of the standard E.W + QCD model(S.M). We briefly comment on this disagreement and on possible new physics explanations which are rather constrained and difficult to implement.
The KOTO experiment recently presented a significant excess of events in their search for the rare SM process $K_L to pi^0 ubar{ u}$, well above both Standard Model signal and background predictions. We show that this excess may be due to weakly-coupled scalars that are produced from Kaon decays and escape KOTO undetected. We study two concrete realizations, the minimal Higgs portal and a hadrophilic scalar model, and demonstrate that they can explain the observed events while satisfying bounds from other flavor and beam-dump experiments. Hadronic beam-dump experiments provide particularly interesting constraints on these types of models, and we discuss in detail the normally underestimated uncertainties associated with them. The simplicity of the models which can explain the excess, and their possible relations with interesting UV constructions, provides strong theoretical motivation for a new physics interpretation of the KOTO data.
The new measurement of the anomalous magnetic momentum of muon at the Fermilab Muon $g-2$ experiment has strengthened the significance of the discrepancy between the standard model prediction and the experimental observation from the BNL measurement. If new physics responsible for the muon $g-2$ anomaly is supersymmetric, one should consider how to obtain light electroweakinos and sleptons in a systematic way. The gauge coupling unification allows a robust prediction of the gaugino masses, indicating that the electroweakinos can be much lighter than the gluino if anomaly-mediated supersymmetry breaking is sizable. As naturally leading to mixed modulus-anomaly mediation, the KKLT scenario is of particular interest and is found capable of explaining the muon $g-2$ anomaly in the parameter region where the lightest ordinary supersymmetric particle is a bino-like neutralino or slepton.
The simplest little Higgs model predicts a light pseudoscalar boson $eta$ and opens up some new decay modes for $Z$-boson, such as $Z to bar{f} f eta$, $Zto etaetaeta$, $Zto etagamma$ and $Zto eta gg$. We examine these decay modes in the parameter space allowed by current experiments, and find that the branching ratios can reach $10^{-7}$ for $Zto bar{b}beta$, $10^{-8}$ for $Zto bar{tau}taueta$, and $10^{-8}$ for $Zto etagamma$, which should be accessible at the GigaZ option of the ILC. However, the branching ratios can reach $10^{-12}$ for $Zto etaetaeta$, and $10^{-11}$ for $Zto eta gg$, which are hardly accessible at the GigaZ option.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
