Related papers: ${}^8$Be Decay Anomaly and Light $Z'$
We present a study of beryllium (Be) abundances in a large sample of field solar-type dwarfs and sub-giants spanning a large range of effective temperatures. The analysis shows that Be is severely depleted for F stars, as expected by the…
We present a systematic evaluation of the shape of the neutrino energy spectrum produced by beta-decay of $^8$B. We place special emphasis on determining the range of uncertainties permitted by existing laboratory data and theoretical…
The possibility that the so-called "lithium problem", i.e. the disagreement between the theoretical abundance predicted for primordial $^7$Li assuming standard nucleosynthesis and the value inferred from astrophysical measurements, can be…
We consider the possible anomaly free Abelian discrete symmetries of the MSSM that forbid the mu-term at perturbative order. Allowing for anomaly cancellation via the Green-Schwarz mechanism we identify discrete R-symmetries as the only…
The Belle II Collaboration reported the first measurement on ${\rm Br}(B^+\rightarrow K^+\nu\bar{\nu})$, which lies 2.7$\sigma$ away from the Standard Model expectation. This result may be manifestation of new physics beyond the Standard…
We present observations of the Be II 313.0 nm resonance doublet in 14 halo and old disk stars with metallicities ranging from [Fe/H]=-0.4 to about -3.0 obtained with the CASPEC spectrograph of the ESO 3.6m telescope at a FWHM about 8.6 km/s…
The Atomiki anomaly can be interpreted as a new light vector boson. If such a new particle exists, it could be a mediator between the Standard Model sector and the dark sector including the dark matter. We discussed some simple effective…
The standard model (SM) of particle physics is spectacularly successful, yet the measured value of the muon anomalous magnetic moment $(g-2)_\mu$ deviates from SM calculations by 3.6$\sigma$. Several theoretical models attribute this to the…
A series of experiments studying neutrinos from intense radioactive sources have reported a deficit in the measured event rate which, in combination, has reached a statistical significance of $\sim 5\sigma$. In this paper, we explore…
There are nine metal-deficient stars that have Li abundances well below the Li plateau that is defined by over 100 unevolved stars with temperatures above 5800 K and values of [Fe/H] $<$ $-$1.0. Abundances of Be have been determined for…
We explore the anomaly-cancellation constraints on simplified dark matter (DM) models with an extra U(1)$^\prime$ gauge boson $Z'$. We show that, if the Standard Model (SM) fermions are supplemented by a single DM fermion $\chi$ that is a…
I study the phenomenology of heavy neutral bosons Z', predicted in GUT-inspired U(1)' models, at the Large Hadron Collider. In particular, I investigate possible signatures due to Z' decays into superymmetric particles, such as chargino,…
The possibility of a significant effect of exotic particles on the Z'->\gamma\gamma\gamma{} and Z->\gamma\gamma\gamma{} decays is investigated in the context of the minimal 331 model. This model, which is based in the SU_C(3)xSU_L(3)xU_X(1)…
In a minimal extension of the Standard Model, in which new neutral fermions have been introduced, we show that the requirement of vanishing anomalies fixes the hypercharges of all fermions uniquely. This naturally leads to electric charge…
In [5] and [19], the authors gave anomaly cancellation formulas for the gauge groups E8,E8*E8. In this paper, we mainly deal with the case of gauge group E8*E8*E8. Using the E8*E8*E8 bundle, we construct some modular forms over SL2(Z). By…
We propose a scenario in which the supersymmetry breaking effect mediated by an additional U(1)' is comparable with that of anomaly mediation. We argue that such a scenario can be naturally realized in a large class of models. Combining…
The EDGES Collaboration has recently reported the detection of a stronger-than-expected absorption feature in the global 21-cm spectrum, centered at a frequency corresponding to a redshift of z ~ 17. This observation has been interpreted as…
We propose a direct search for the X17 particle, which was conjectured to explain the ATOMKI $^8$Be and $^4$He anomalies, through the dilepton photoproduction process on a nucleon in the photon energy range below or around the pion…
We report on a search for the free decay component of pi- stopped in water and light materials. A non-zero value of this would be an indication of anomalous nu_e contamination to the nu_e and nu_mu_bar production at stopped-pion neutrino…
The Standard Model's accidental and anomaly-free currents: $B-L$, $L_e-L_\mu$, $L_e-L_\tau$, and $L_\mu-L_\tau$, could be indicative of a hidden gauge structure beyond the Standard Model. Additionally, neutrino masses can be generated by a…