Contribution to the proceedings of the 18th International Conference on B-Physics at Frontier Machines (Beauty 2019), Ljubljana, Slovenia, September 30 - October 4, 2019
The LHCb and Belle collaborations have reported on some anomalies in $b \to s$ transitions, with discrepancies with the Standard Model predictions in some angular observables and branching ratios and intriguing hints for lepton universality violation. We will review the current situation and explore the proposed New Physics explanations for these tensions. We will also discuss the possible connection of the $b \to s$ anomalies to other central problems in physics, such as the dark matter of the Universe, the origin of neutrino masses or the strong CP problem.
The LHC has collided protons on protons at center-of-mass energies of 7 and 8 TeV between 2010-2012, referred to as the Run I period. We review the current status of searches for new physics beyond the Standard Model at the end of Run I by the ATLAS and CMS experiments, limited to the 8 TeV search results published or submitted for publication as of the end of February 2014. We discuss some of the implications of these searches on the existence of TeV scale new physics, with a special focus on two open questions: the hierarchy problem, and the nature of dark matter. Finally, we give an outlook…
Recent measurements have revealed a number of intriguing deviations from the Standard Model predictions in $B$ meson decays, in particular in observables testing lepton flavour universality. We review their experimental status and theoretical description in terms of effective Hamiltonians. We also discuss possible new physics interpretations in terms of simplified models and summarise their status in view of the stringent constraints from flavour physics and high-$p_T$ collider searches.
With the historic discovery of the Higgs boson our picture of particle physics would have been complete were it not for the neutrino sector and cosmology. I briefly discuss the role of neutrino masses and mixing upon gauge coupling unification, electroweak breaking and the flavor sector. Time is ripe for new discoveries such as leptonic CP violation, charged lepton flavor violation and neutrinoless double beta decay. Neutrinos could also play a role in elucidating the nature of dark matter and cosmic inflation.
This is a pedagogical review of the recent observational data obtained from type Ia supernova surveys that support the accelerating expansion of the universe. The methods for the analysis of the data are reviewed and some of the theoretical implications obtained from their analysis are discussed.
The experimental evidences in favor of oscillations of solar (and KamLAND) and atmospheric (and K2K) neutrinos are briefly reviewed and accommodated in the framework of three-neutrino mixing. The implications for the values of neutrino masses are discussed and the bounds on the absolute scale of neutrino masses from Tritium beta-decay and cosmological data are reviewed. Finally, we discuss the implications of three-neutrino mixing for neutrinoless double-beta decay.
We present a status report on the indirect searches for New Physics performed by means of heavy flavour decays. Particular attention is devoted to the recent experimental results in B and charm physics obtained by the LHC experiments. The implications of these results for physics beyond the Standard Model are discussed both in general terms and by means of a few specific examples.
The theoretical status of the muon anomaly is reviewed including the recent change in the light by light hadronic correction. Specific attention is given to the implications of the shift in the difference between the BNL experimental result and the standard model prediction for sparticle mass limits. The implication of the BNL data for Yukawa unification is discussed and the role of gaugino mass nonuniversalities in the satisfaction of Yukawa unification is explored. An analysis of the BNL constraint for the satisfaction of the relic density constraint and for the search for dark matter is als…
In the framework of renormalisable relativistic quantum field theory, the explanation of neutrino masses necessarily requires the existence of new physical states. These new states may also be responsible for other unexplained phenomena in particle physics and cosmology. After a brief introduction, I focus on scenarios in which the neutrino masses are generated by the type-I seesaw mechanism and review the phenomenological implications of different choices of the seesaw scale.
This article reviews some recent developments in Astroparticle Physics. Due to the extension of the field only part of the results and developments can be covered. The status of the search for Dark Matter, some recent results on Cosmic Rays and Gamma Ray Astronomy and the status of Neutrino Astronomy are presented.
Neutrinoless double-beta decay is a forbidden, lepton-number-violating nuclear transition whose observation would have fundamental implications for neutrino physics, theories beyond the Standard Model and cosmology. In this review, we summarize the theoretical progress to understand this process, the expectations and implications under various particle physics models, as well as the nuclear physics challenges that affect the precise predictions of the decay half-life. We will also provide a synopsis of the current and future large-scale experiments that aim at discovering this process in physi…
Evidence for an accelerated expansion of the universe as it has been revealed ten years ago by the Hubble diagram of distant type Ia supernovae represents one of the major modern revolutions for fundamental physics and cosmology. It is yet unclear whether the explanation of the fact that gravity becomes repulsive on large scales should be found within general relativity or within a new theory of gravitation. However, existing evidences for this acceleration all come from astrophysical observations. Before accepting a drastic revision of fundamental physics, it is interesting to critically exam…
For the first time, the Fermi-LAT measured the angular power spectrum (APS) of anisotropies in the diffuse gamma-ray background. The data is found to be broadly compatible with a model with contributions from the point sources in the 1-year catalog, the galactic diffuse background, and the extragalactic isotropic emission; however deviations are present at both large and small angular scales. In this study, we complement the model with a contribution from Dark Matter (DM) whose distribution is modeled exploiting the results of the most recent N-body simulations, considering the contribution of…
For decades, the unnaturalness of the weak scale has been the dominant problem motivating new particle physics, and weak-scale supersymmetry has been the dominant proposed solution. This paradigm is now being challenged by a wealth of experimental data. In this review, we begin by recalling the theoretical motivations for weak-scale supersymmetry, including the gauge hierarchy problem, grand unification, and WIMP dark matter, and their implications for superpartner masses. These are set against the leading constraints on supersymmetry from collider searches, the Higgs boson mass, and low-energ…
In this talk we discuss the constraints on supersymmetry arising from data from a number of recent experiments. There appears to be good cumulative evidence from experiment in favor of positivity of the sign of the Higgs mixing parameter $μ$. Implications of this result for Yukawa unification are discussed since Yukawa unification is sensitive to the $μ$ sign. An analysis of dark matter under the constraints of Yukawa unification is also given. It is shown that the simultaneous imposition of all existing constraints sharply defines the parameter space of models. Specifically models with nonuni…
We investigate the implications of scalar and tensor operators proposed to accommodate the hints of lepton flavor universality violation in charged-current $B$-meson decays. We show that these scenarios unavoidably induce chirality enhanced contributions to charged lepton magnetic moments and Yukawa couplings. By using an effective field theory approach we quantify in a model independent way the connection of the $R_{D^{(\ast)}}$ anomaly with the tau $g-2$ and the Higgs decay $h\to ττ$, which can offer an alternative to test these scenarios. Concrete New Physics models giving rise to our setup…
There are many reasons to believe that there might be new sources of CP-violation beyond the phases of the KM matrix. One of these is the possibility of electroweak baryogenesis. We describe some recent developments in this subject and make some comments on the possibility that the minimal standard model might itself be the origin of the baryon asymmetry. To appear in the Proceedings of the Third KEK Topical Conference on CP Violation, its Implications to Particle Physics and Cosmology, 16--18 November, 1993.
Very compact objects probe extreme gravitational fields and may be the key to understand outstanding puzzles in fundamental physics. These include the nature of dark matter, the fate of spacetime singularities, or the loss of unitarity in Hawking evaporation. The standard astrophysical description of collapsing objects tells us that massive, dark and compact objects are black holes. Any observation suggesting otherwise would be an indication of beyond-the-standard-model physics. Null results strengthen and quantify the Kerr black hole paradigm. The advent of gravitational-wave astronomy and pr…
The observational evidence for the recent acceleration of the universe demonstrates that canonical theories of cosmology and particle physics are incomplete---if not incorrect---and that new physics is out there, waiting to be discovered. A key task for the next generation of laboratory and astrophysical facilities is to search for, identify and ultimately characterize this new physics. Here we highlight recent developments in tests of the stability of nature's fundamental couplings, which provide a direct handle on new physics: a detection of variations will be revolutionary, but even improve…
If the dark energy equation of state parameter w(z) crosses the phantom divide line w=-1 (or equivalently if the expression d(H^2(z))/dz - 3Ω_m H_0^2 (1+z)^2 changes sign) at recent redshifts, then there are two possible cosmological implications: Either the dark energy consists of multiple components with at least one non-canonical phantom component or general relativity needs to be extended to a more general theory on cosmological scales. The former possibility requires the existence of a phantom component which has been shown to suffer from serious theoretical problems and instabilities. Th…
