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Física Teórica
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Física Teórica
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Física Teórica
- Sven Heinemeyer (IFCA (CSIC))
We present the first comprehensive study of fragmentation into fully heavy tetraquarks, based on the newly released TQ4Q1.1 set of collinear, variable-flavor-number-scheme fragmentation functions. Covering scalar ($0^{++}$), axial-vector ($1^{+-}$), and tensor ($2^{++}$) configurations, our analysis provides a pioneering framework to explore exotic-matter production with precision QCD tools....
Abstract:
Quantum Chromodynamics predicts that protons are shaped not only by parton densities but also by quantum interference between quarks and gluons. In this talk I'll present our most recent work on the extraction of this interference effects, establishing their presence at a 2-3 sigma significance.
Neutrinos are a valuable probe for measuring Parton Distribution Functions (PDFs) due to the flavor-dependent nature of their interactions with quarks. Recent comparisons between neutrino-nucleon and charged lepton-nucleon deep inelastic scattering (DIS) data show emerging tensions, which may lead to neutrino exclusive nuclear physics. However, previous neutrino studies have been hindered, in...
We present a discussion of effective CP-violating interactions of electrons with nucleons emerging from a heavy scalar sector linearly realized. In particular, we investigate the aligned 2HDM in the decoupling limit. This model which contains sources of CP-violation that, after integrating out the heavy scalars, generate 4-fermion operators.
There are operators involving both a lepton current...
In this talk, a dispersive approach is presented to extract the s-wave $\eta\pi$ scattering phase shift in the elastic regime from BESIII $\eta^{\prime} \rightarrow \eta \pi \pi $ experimental data. This approach relies on unitarity and the structure of two-body partial wave amplitudes with an analytical closed formula for the Right-Hand-Cut and a conformal mapping for the Left-Hand-Cut....
Quantum Chromodynamics (QCD) dictates that in extreme conditions, as those reproduced in heavy-ion collisions, hadronic matter turns into a new form of elementary matter: the quark-gluon plasma (QGP). The theoretical interpretation of QCD jet observables in heavy-ion collisions is nonetheless to this day a complex task and there are still competing explanations for the physical origin of the...
The transverse momentum dependent (TMD) factorization theorem incorporates several types of power corrections to the leading term. For large values of transverse momentum, $q_T/Q$ corrections become significant. They arise from higher-twist TMD distribtuions, which are singular at small transverse distances. We propose a method that reveals this singularity and makes the $q_T/Q$ correction...
We perform dimensional reduction of the electroweak sector of the dimension-six SMEFT to order $\mathcal{O}(g^4)$ in coupling constants $g$. This analysis includes one-loop contributions to kinetic terms and quartic couplings; as well as two-loop contributions, where operators such as four-fermion interactions first appear, to squared mass terms. Using lattice data, we also provide evidence...
In this work, we study the renormalization-group evolution of parameters in the dimensionally reduced three-dimensional effective field theory (3D EFT) that describes thermally driven electroweak phase transitions of the Standard Model Higgs field, triggered by Beyond the Standard Model physics.
We compute the two-loop running of the 3D EFT including the effect of the leading...
Skyrmions were first proposed in QCD, where they provide a topological description of baryons as solitonic excitations of the pion field. Their emergence as a new degree of freedom without the need of additional field content, and their potential as a dark matter candidate, has since motivated the search for analogous configurations in other theories.
In this work, we shall address the search...
We determine the expression for the entanglement entropy at finite temperature for disk regions in conformal field theories that are dual to black holes in Einstein gravity and Gauss-Bonnet gravity, in the context of the AdS/CFT correspondence. We use the Ryu-Takayanagi formula and its generalization for higher-curvature gravities, respectively. We compute the low temperature expansion of the...
Dimensional regularization is nowadays the most used technique to perform loop calculations in Quantum Field Theories. However, it faces some complications when applied to chiral gauge theories such as the Standard Model of particle physics because it is not possible to define a mathematically consistent D-dimensional scheme that preserves gauge symmetries. Nonetheless, for a theory free of...
We present a novel approach to compute two-loop beta functions in effective field theories obtained via dimensional reduction from five to four dimensions. We isolate UV divergences in the 4D theory from the IR divergences arising in the matching procedure (remarkably 1 and 2 loop UV divergences in 5D vanish). This method provides a straightforward way to disentangle 4D from 5D contributions,...
We discuss various aspects of multi-Higgs boson production from longitudinal electroweak (EW) gauge boson scattering in the TeV region as the necessary information to characterise the Flare function, F(h), which determines whether the Standard Model EFT (SMEFT) or the Higgs EFT (HEFT -also sometimes referred as the EW Chiral Lagrangian-) is the appropriate description. We analyze various...
In this work we analyze how NA64μ can contribute to the global SMEFT program by probing two effective four lepton operators completely unbounded so far and break one of the current flat directions. Furthermore, we also study the potential of NA64 testing an extension of SMEFT that includes fermion singlets of the SM gauge group in the low energy field content. This effective field theory,...
We propose an extension of the electroweak sector of the Standard Model in which the gauge group $SU(2)_L$ is promoted to $SU(2)_1 \times SU(2)_2$. This framework naturally includes a viable dark matter candidate and generates neutrino masses radiatively à la Scotogenic. Our scenario can be viewed as an ultraviolet extension of the Scotogenic mechanism, addressing some of its shortcomings....
Baryon and lepton number are excellent low-energy symmetries of the Standard Model (SM) that tightly constrain the form of its extensions. In this paper we investigate the possibility that these accidental symmetries are violated in the deep UV, in such a way that one multiplet necessary for their violation lives at an intermediate energy scale M above the electroweak scale. We write down the...
The lack of observation of experimental signals pointing to the existence of physics beyond the Standard Model (SM) suggests that the coupling between SM particles and hidden sectors is likely small. This suppression leads to relatively long lifetimes for BSM particles when their masses lie within the MeV–GeV range. In this talk, the regime of long-lived particles (LLPs) is considered,...
Neutrino non-standard interactions (NSI) have been studied in a variety of contexts and suggested as a possible mechanism for resolving certain unexpected results in oscillation experiments. NSI may be generated in various ways and take a variety of forms. We focus on flavor-changing neutral current NSIs involving tau neutrinos. In simple scenarios in which these are generated by dimension-six...
Modular symmetries have emerged as a promising and elegant approach to the flavor problem, with the discrete group $A_4$ as a benchmark example. In this work, we study the impact of modular UV interactions generating dimension-6 SMEFT operators with leptons. Restricting to extensions with a single mediator and at most one modular form insertion, we classify the possible scenarios and compute...
We show that, contrary to common expectations, the observed charged leptons can have a substantial mixing with new, heavier fermions. This can happen, in the language of effective theories, when the effect of mixing with heavier fermions vanishes at tree level in operators of mass-dimension 6 (or it is suppressed by the small charged lepton masses), a cancellation that can be naturally ensured...
The temperature and polarization of the cosmic microwave background (CMB), as measured today, may offer key insights into the topology of the early universe prior to inflation, for example, by discriminating between flat and warped geometries. In this paper, we focus on a Kaluza-Klein model with an extra spatial dimension that compactifies at the Grand Unified Theory (GUT) epoch, subject to...
Apart from its gravitational interactions, dark matter (DM) has remained so
far elusive in laboratory searches. One possible explanation is that the relevant interactions
to explain its relic abundance are mainly gravitational. In this work we consider an extra-
dimensional Randall-Sundrum scenario with a TeV-PeV IR brane, where the Standard
Model is located, and a GeV-TeV deep IR (DIR) one,...
