Fitxa persona

Scientific Career:

In 1987-88, I was a postdoc at Carnegie Mellon University, Pittsburgh (USA). In 1989-90, I was a postdoc at the Max Planck Institute for Physics in Munich, Germany. In 1989, I obtained a tenured position as Associate Professor at the University of Valencia through a competitive examination. From 1992-94, I held a CERN fellowship at CERN, Geneva, Switzerland. In 2007, I obtained the qualification for Full Professor through a competitive examination, and since 2008, I have been a Full Professor at the University of Valencia.

Research lines and key contributions:

1. Quantum Corrections in the Standard Model:
   Various results have been obtained in this area, but perhaps the most significant is the discovery of the non-decoupling effects of the top quark in the Z-b-b interaction. This result was published at the time and was essential in determining the top quark mass at LEP before its discovery at Fermilab (Bernabéu, Pich & Santamaria).

2. Massive Neutrinos:
   Recently, we have confirmed that neutrinos do indeed have mass. However, there is still no “standard model of massive neutrinos.” It is therefore crucial to develop a model capable of describing all experimental data and that can be tested in the future. In this field, we have published several high-impact articles proposing and studying different models to explain the small neutrino masses (with Bertolini, Valle, Nebot, Oliver, Palao, del Águila, Bhattacharya, Aparici, Wudka, Herrero-Garcia, Rius, Das, Alcaide).

3. Higgs Boson Physics in the Standard Model and Its Extensions:
   The Higgs boson has finally been discovered at the LHC, and exploring its properties is crucial. We have been working in this area for some time. We studied the possibility of the Higgs boson decaying invisibly into other scalars (Bertolini & Santamaria). Recently, CMS and ATLAS reported hints of Higgs decays violating lepton flavor, and we have thoroughly explored this possibility (Herrero-Garcia, Rius & Santamaria). We have also analyzed the scalar mass spectrum in a model with scalar triplets, considering the known properties of the Higgs boson (Das & Santamaria).

4. Tau Lepton Physics:
   A phenomenological resonance model was developed to describe tau lepton decays into two and three pions, which has been widely used (Kühn & Santamaria). Additionally, the magnetic moment of the tau lepton was determined using experimental data from LEP (Gonzalez-Springer, Santamaria & Vidal).

5. Particles in Astrophysics:
   In this field, aside from implications for specific models, a key contribution was the systematic study of new neutrino interactions in supernova cooling (Choi & Santamaria).

    

6. Effective Quantum Field Theories (EFTs):
   We have studied, in general, the use of EFTs to analyze new physics (Bilenky & Santamaria) and to simplify the calculation of radiative corrections in renormalizable theories (Peris & Santamaria). In recent years, we have also used EFTs to describe neutrino masses in the most model-independent way possible (del Águila, Aparici & Wudka).

7. Theories with Extra Dimensions:
   We have analyzed the quantum effects of additional dimensions in the decay of the Z boson into b quarks (Oliver, Papavassiliou & Santamaria). Additionally, we have studied the calculability of quantum effects that grow with energy in such models. Controlling these effects is essential for constructing a theory that unifies all interactions at experimentally accessible energy scales (Oliver, Papavassiliou & Santamaria).

8. Mass Running and QCD:
   In quantum field theories, mass appears as another parameter of the theory, almost at the same level as coupling constants. As such, it is not a fixed quantity but varies with energy. However, until recently, the variation of mass with energy had never been experimentally verified. A key milestone was suggesting that the LEP experiment might have the necessary precision to test the energy dependence of the b quark mass (Bilenky, Rodrigo & Santamaria). This verification required highly complex calculations by our group and a sophisticated experimental analysis carried out by the DELPHI collaboration in Valencia (Fuster et al.). Thanks to this collaboration between theoretical and experimental groups in Valencia, we can now confirm that quark masses evolve with the energy scale.