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Achille Stocchi

Publications and source records attributed to Achille Stocchi.

12 recordsLinked to original sources
arXiv2025

Enhancing European Cooperation in the Search for Dark Matter

The search for dark matter is an exciting topic that is pursued in different communities over a wide range of masses and using a variety of experimental approaches. The result is a strongly correlated matrix of activities across Europe and beyond, both on the experimental and the theoretical side. We suggest to encourage and foster the collaboration of the involved institutions on technical, scientific and organisational level, in order to realise the synergies that are required to increase the impact of dark matter research and to cope with the increasing experiment sizes. The suggested network -- loosely titled "DMInfraNet" -- could be realised as a new initiative of the European strategy or be based on existing structures like iDMEu or DRD. The network can also serve as a nucleus for future joint funding proposals.

hep-ex↗
arXiv2022

New UTfit Analysis of the Unitarity Triangle in the Cabibbo-Kobayashi-Maskawa scheme

Flavour mixing and CP violation as measured in weak decays and mixing of neutral mesons are a fundamental tool to test the Standard Model (SM) and to search for new physics. New analyses performed at the LHC experiment open an unprecedented insight into the Cabibbo-Kobayashi-Maskawa (CKM) metrology and new evidence for rare decays. Important progress has also been achieved in theoretical calculations of several hadronic quantities with a remarkable reduction of the uncertainties. This improvement is essential since previous studies of the Unitarity Triangle did show that possible contributions from new physics, if any, must be tiny and could easily be hidden by theoretical and experimental errors. Thanks to the experimental and theoretical advances, the CKM picture provides very precise SM predictions through global analyses. We present here the results of the latest global SM analysis performed by the UTfit collaboration including all the most updated inputs from experiments, lattice QCD and phenomenological calculations.

hep-ph↗
arXiv2017

Unitarity Triangle Analysis in the Standard Model and Beyond

Flavour physics represents a unique test bench for the Standard Model (SM). New analyses performed at the LHC experiments are now providing unprecedented insights into CKM metrology and new evidences for rare decays. The CKM picture can provide very precise SM predictions through global analyses. We present here the results of the latest global SM analysis performed by the UTfit collaboration including all the most updated inputs from experiments, lattice QCD and phenomenological calculations. In addition, the Unitarity Triangle (UT) analysis can be used to constrain the parameter space in possible new physics (NP) scenarios. We update here also the UT analysis beyond the SM by the UTfit collaboration. All of the available experimental and theoretical information on $ΔF=2$ processes is reinterpreted including a model-independent NP parametrisation. We determine the allowed NP contributions in the kaon, $D$, $B_d$, and $B_s$ sectors and, in various NP scenarios, we translate them into bounds for the NP scale as a function of NP couplings.

hep-ph↗
arXiv2014

Standard Model updates and new physics analysis with the Unitarity Triangle fit

We present here the update of the Unitarity Triangle (UT) analysis performed by the UTfit Collaboration within the Standard Model (SM) and beyond. Continuously updated flavour results contribute to improving the precision of several constraints and through the global fit of the CKM parameters and the SM predictions. We also extend the UT analysis to investigate new physics (NP) effects on $ΔF=2$ processes. Finally, based on the NP constraints, we derive upper bounds on the coefficients of the most general $ΔF=2$ effective Hamiltonian. These upper bounds can be translated into lower bounds on the scale of NP that contributes to these low-energy effective interactions.

hep-ph↗
arXiv2011

Physics Opportunities at the Next Generation of Precision Flavor Physics

Starting with next-generation experiments, flavor physics fully enters the era of precision measurements. The focus shifts from testing the Standard Model to finding and characterizing new physics contributions. We review the opportunities offered by future flavor experiments, discussing the expected sensitivities of the most important measurements. We also present some examples of measurable deviations from the Standard Model in the flavor sector generated in a selection of new physics models, demonstrating the major contribution that precision flavor physics could give to the effort of going beyond the Standard Model.

hep-ph↗
arXiv2004

Current Status of the CKM Matrix and the CP Violation

These lectures give an introduction and the current status of flavour physics in the quark sector, with special attention to the CKM matrix and CP violation. We describe the measurements which contribute to the determination of the CKM matrix elements and how, together with important theoretical developments, they have significantly improved our knowledge on the flavour sector of the Standard Model. These lectures are complemented by the seminar of U. Mallik (see these proceedings) which describes in more details the most recent CP-violating related measurements by the B-factories. The results presented are up-to-date till winter 2004.

hep-ph↗
arXiv2002

The CKM Matrix and The Unitarity Triangle: Another Look

The unitarity triangle can be determined by means of two measurements of its sides or angles. Assuming the same relative errors on the angles $(α,β,γ)$ and the sides $(R_b,R_t)$, we find that the pairs $(γ,β)$ and $(γ,R_b)$ are most efficient in determining $(\bar\varrho,\barη)$ that describe the apex of the unitarity triangle. They are followed by $(α,β)$, $(α,R_b)$, $(R_t,β)$, $(R_t,R_b)$ and $(R_b,β)$. As the set $\vus$, $\vcb$, $R_t$ and $β$ appears to be the best candidate for the fundamental set of flavour violating parameters in the coming years, we show various constraints on the CKM matrix in the $(R_t,β)$ plane. Using the best available input we determine the universal unitarity triangle for models with minimal flavour violation (MFV) and compare it with the one in the Standard Model. We present allowed ranges for $\sin 2β$, $\sin 2α$, $γ$, $R_b$, $R_t$ and $ΔM_s$ within the Standard Model and MFV models. We also update the allowed range for the function $F_{tt}$ that parametrizes various MFV-models.

hep-ph↗
arXiv1999

$B^0 - \bar{B}^0$ oscillations and measurements of $|V_{ub}|/|V_{cb}|$ at LEP

In this paper a review of the LEP analyses on $B^0 - \bar{B}^0$ oscillations and on the measurement of $|V_{ub}|/|V_{cb}|$ is presented . These measurements are of fundamental importance in constraining the $ρ$ and $η$ parameters of the CKM matrix. A review of the current status of the $V_{CKM}$ matrix determination is also given.

hep-ex↗
arXiv1997

Alternative Theories of CP violation

Recent improvements to the limit of Delta M_{B_s} imply that pure superweak theories, while not excluded, no longer provide a good fit to the data. A class of general superweak theories is introduced in which all flavor changing interactions are governed by an approximate flavor symmetry which gives a ``3 mechanism''. These theories are in good agreement with data, and predict low values for |V_{td}|, |V_{ub}/V_{cb}|, B(K^+ to pi^+ nu nubar), epsilon'/epsilon and CP asymmetries in B decays, and high values for Delta M_{B_s} and f_B sqrt{B_B}. An important example of such a theory is provided by weak scale supersymmetric theories with soft CP violation. The CP violation originates in the squark mass matrix, and, with phases of order unity, flavor symmetries can yield a correct prediction for the order of magnitude of epsilon_K.

hep-ph↗