New Frontiers in Theoretical Physics - XXXVIII Convegno Nazionale di Fisica Teorica

Session

Hadron/Flavor/Lattice

22 May 2025, 15:10

Palazzone della Scuola Normale Superiore di Pisa, Cortona

141. Isospin Strikes Back

Francesco Rosini (Istituto Nazionale di Fisica Nucleare)

22/05/2025, 15:10

The decay of a charmonium vector meson $c\bar c$ into the $\Lambda\bar\Sigma^0 + \mathrm{c.c.}$ state can be considered purely electromagnetic under the assumption of isospin conservation. The first-order interaction is therefore mediated by a virtual photon, similar to the non-resonant process $e^+e^- \to \Lambda\bar\Sigma^0 + \mathrm{c.c.}$ in the Born approximation. Given the nature of...

162. RG running and mixing for $\Delta F = 2$ Four-Fermion Operators in $\chi SF$ schemes

Riccardo Marinelli (Istituto Nazionale di Fisica Nucleare)

22/05/2025, 15:25

We study the renormalization and mixing of the $\Delta F=2$ Four-Fermion Operators (FFO), starting from the problem of the computation of the perturbative running for $N_\mathrm{f}=3$ and showing how this problem is solved through the use of the Poincaré-Dulac theorem. We then illustrate the procedure to evaluate the non-perturbative running from the hadronic scale ($O(\Lambda_{QCD})$) to the...

164. The Cabibbo Angle from Inclusive $\tau$ Decays

Francesco Sanfilippo (Istituto Nazionale di Fisica Nucleare)

22/05/2025, 15:40

The inclusive hadronic decays of the $\tau$ lepton offer an alternative method for extracting the CKM matrix elements $V_{\mathrm{ud}}$ and $V_{\mathrm{us}}$. In this talk, I will discuss recent results from the ETM Collaboration on the inclusive hadronic decay rate of the $\tau$, obtained in $N_f=2+1+1$ QCD using the novel HLT method. This approach circumvents the well-known inverse Laplace...

166. Determination of the $\Lambda$--parameter of $\mathrm{SU}(N)$ Yang--Mills theories in the Twisted Gradient Flow scheme on the lattice

Andrea Giorgieri (Istituto Nazionale di Fisica Nucleare)

22/05/2025, 15:55

We present our preliminary determinations of the $\Lambda$--parameter of $\mathrm{SU}(N=3,5,8)$ Yang--Mills theories and of its large--$N$ limit in the Twisted Gradient Flow renormalization scheme on the lattice. First, we determine $\Lambda$ in units of a low-energy renormalization scale $\mu_{\mathrm{had}}$ using the step-scaling method. Then, to express $\Lambda$ in units of the...

144. Study of the scalar and pseudoscalar meson mass spectrum of QCD above the chiral transition, using an effective Lagrangian approach

Dr Giulio Cianti (Sapienza Università di Roma)

22/05/2025, 16:40

The fundamental theory of strong interactions, known as Quantum ChromoDynamics (QCD), exhibits rich symmetry properties that underlie the behavior of hadronic matter. In the limit of $N_f$ light quark masses, QCD possesses an approximate chiral symmetry $U(1)_V\otimes U(1)_A\otimes SU(N_f)_V\otimes SU(N_f)_A$. The special unitary part of this symmetry group is spontaneously broken to its...

153. The $X(3872)$ Puzzle: Insights from Effective Field Theories

Davide Germani (Sapienza Università di Roma e Istituto Nazionale di Fisica Nucleare), Davide Germani (Sapienza Università di Roma & Istituto Nazionale di Fisica Nucleare)

22/05/2025, 16:55

The (in)famous $X(3872)$ was the first exotic particle discovered in 2003, compatible with a tetraquark interpretation. More than twenty years have passed since then, yet its internal dynamic remain an open question. Currently, the most established models describe the $X(3872)$ either as a compact tetraquark, where quarks interact via color forces, or as a $\bar{D}^0D^{0}$ mesonic molecule,...