This year marks the \(350^{\mathrm {th}}\) anniversary of the discovery of the first animalcula (little animals) by van Leeuwenhoek in 1676. Flavour physics makes it possible to search for new animalcula at distance scales far shorter than those resolved by van Leeuwenhoek in 1676, and even shorter than those directly accessible at the Large Hadron Collider and the planned colliders in this century. I summarize various strategies for achieving this goal. While precise measurements of a wide variety of observables and their precise theoretical calculations, both within the Standard Model (SM) and beyond it, are indispensable in this context, in my view, it is crucial to develop strategies for the search for New Physics (NP) that go beyond the global fits that are very popular today. While effective field theories such as WET and SMEFT are formulated in terms of Wilson coefficients of the relevant operators, with correlations characteristic of the SM and of specific NP scenarios, the most direct tests of the SM and its extensions are, in my opinion, correlations among different observables, like branching ratios of numerous decays, that are characteristic of particular new animalcula at work. Abstract Published by the Jagiellonian University 2026 authors

Germany

A.J. Buras

Hunting New Animalcula with Flavour Changing Processes

In a recently proposed approach to testing models of inflation by Cosmic Microwave Background (CMB) radiation, the reheating temperature is directly expressed in terms of the CMB observables. Its model-independent bounds translate in a given model into narrow ranges of those observables. In that approach, we analyse the polynomial class of the \(\alpha \)-attractor inflaton potential models (P-models), in a broad range of polynomials and with the inflaton decays and fragmentation in the reheating period taken into account. The predictions for the CMB observables, the scalar spectral index \(n_{\mathrm {s}}\) and tensor-to-scalar ratio \(r\), are compared with the Planck and Planck combined with ACT data. Both can be accommodated by that class of the \(\alpha \)-attractor models. The sensitivity of the results of that comparison to the reheating temperature and to the upper bound on the ratio \(r\) is clearly demonstrated. Abstract Published by the Jagiellonian University 2026 authors

Poland

M. Marciniak

M. Olechowski

S. Pokorski

Testing \(\alpha \)-attractor P-model of Inflation by Cosmic Microwave Background Radiation

We examine the Regge theoretical properties for the scaling observed in \(pp\) elastic scattering differential cross sections at the LHC. A positive signature amplitude (&lt;span class="it"&gt;i.e.&lt;/span&gt; the Pomeron) with scaling properties has been derived. It is found to describe the dip–bump region of momentum transfer at LHC energies in agreement with data. We derive the analytic continuation in the whole plane of the \(t\)-channel partial waves of index \(l_t\) specific to the Regge formalism. The analytic form of the partial-wave amplitude exhibits a specific scaling property without singularities, except for a series of poles in the \(l_t\) real axis at fractional values. Abstract Published by the Jagiellonian University 2026 authors

France

R. Peschanski

B.G. Giraud

The Scaling Pomeron

This contribution reviews recent progress in the low-lying scalar mesons and glueballs. We propose a new classification for the scalar nonet that includes \(f_0(980)\) and \(a_0(980)\) as the lowest states, while we identify \(f_0(1500)\) as a primary glueball candidate. We demonstrate that the production yields of these states in heavy-ion collisions are mutually consistent across statistical, coalescence, and S-matrix frameworks. To investigate their internal structure, we move beyond standard phenomenology by describing glueballs as topological solitons. This approach yields an energy spectrum in excellent agreement with lattice QCD and experimental data, while interpreting \(f_0(2470)\) as a tightly bound glueballonium to explain its anomalously long lifetime. This non-perturbative framework provides a predictive basis for the future experimental verification of exotic scalar states. Abstract Published by the Jagiellonian University 2026 authors

C. Sasaki

Selected Topics in Quark–Hadron Physics: From Scalar Nonets to Topological Glueballs

QCD at finite isospin density is considered for a large number of colors \(N_c\). A linear sigma model is used to model the meson content of the theory at low density. At isospin chemical potential \(\mu _I \ll {\mit \Lambda }_{\mathrm {QCD}}\), this matter forms a Bose condensate. For \(\mu _I \gg \sqrt {N_c} {\mit \Lambda }_{\mathrm {QCD}}\), unlike QCD, remains confined, but the degrees of freedom of the system are mesons and Cooper pairs bound on size scales small compared to the QCD size scale determined by the superfluid gap. For most purposes, this matter may be analyzed using weak coupling methods. For \( {\mit \Lambda }_{\mathrm {QCD}} \le \mu _I \le \sqrt {N_c} {\mit \Lambda }_{\mathrm {QCD}}\), we argue that meson matter is quarkyonic, with quarks bound into mesons on a size scale of order \({\mit \Lambda }_{\mathrm {QCD}}\) corresponding to a filled Fermi sea of quarks, with possible Bose condensation at the Fermi surface and/or Cooper pairs with a finite width of the surface of order \({\mit \Lambda }_{\mathrm {QCD}}\). Abstract Published by the Jagiellonian University 2026 authors

United States

Larry McLerran

Quarkyonic Meson Matter for Finite Isospin Density

We discuss first the discovery of the odderon by the TOTEM and D0 collaborations. We then describe the gap between jet measurements sensitive to the high gluon density regime and the possible observation of the saturation phenomenon in PbPb interactions. We also mention the sensitivity to beyond the Standard Model physics and to the production of axion-like particles via photon–photon interactions. Abstract Published by the Jagiellonian University 2026 authors

C. Royon

Diffractive and Photon-Induced Processes at the LHC: From the Odderon Discovery, the Evidence for Saturation to the Search for Axion-like Particles

Gluon and graviton radiation in strong field shockwave scattering are described by effective Lipatov vertices, with the graviton Lipatov vertex proportional to the bilinear of its QCD counterpart. We show here that the \(n\)-particle gluon radiation spectrum can be described as a generalized Susskind–Glogower (gSG) squeezed coherent state and discuss the properties of such squeezed states. The double-copy structure of the radiative frameworks suggests that multi-graviton radiation can be similarly described as a gSG state. We examine the physical parameter space and show that very large squeezing parameters \(\sim \ln ({\bar n})\) (where \({\bar n}\) is the mean graviton occupancy) are feasible for nearly minimal uncertainty configurations of the gSG state. Quantum noise in the corresponding gravitational wave spectrum is enhanced above the sensitivity of current and future gravitational wave detectors. Our results point to the importance of a comprehensive study of the strong field Lipatov regime of gravitational radiation. Abstract Published by the Jagiellonian University 2026 authors

A.M. Staśto

H. Raj

R. Venugopalan

Squeezed State Radiation in Shockwave Scattering: QCD–Gravity Double Copy

We provide an elementary pedagogical introduction to some basic concepts and techniques of soft (or Sudakov) resummation, specifically in QCD, paying particular attention to simple but useful tricks of the trade. We briefly review collinear (Altarelli–Parisi) and infrared (eikonal) factorization, cancellation of infrared singularities, and factorization of mass singularities. We recall basic concepts on renormalization group invariance and the solution of renormalization group equations. We then show how threshold resummation can be derived from a renormalization group argument following from the cancellation of infrared singularities. We discuss various equivalent forms of the resummed result, and we briefly present transverse momentum resummation. Abstract Published by the Jagiellonian University 2026 authors

Italy

S. Forte

G. Ridolfi

A Simple Introduction to Soft Resummation

The Roper resonance \(N^\ast (1440)\) was discovered by David Roper in 1964 through sophisticated partial-wave analyses of \(\pi N\) scattering data. However, the first direct observation of the Roper resonance peak in the \(\pi N\) invariant mass spectrum was only realized 40 years later from the charmonium decay \(J/\psi \to \bar pn\pi ^+ +\mathrm {c.c.}\) at the Beijing Electron–Positron Collider. Further observations of the Roper resonance production from various charmonium decays helped reveal its multiquark nature, with a large \(\sigma N\) component. Abstract Published by the Jagiellonian University 2026 authors

B.S. Zou

Roper Resonance \(N^\ast (1440)\) from Charmonium Decays

The first baryon resonance was discovered in the early 1950s. The Roper resonance joined the collection ten years later. Today, many baryon resonances are known and more are being discovered. As baryons, these states are the most fundamental three-body systems in Nature. They must all be understood, not just the isolated ground-state nucleon. This contribution sketches applications of continuum Schwinger function methods to the baryon resonance problem. Whilst spectroscopy is of value, particular emphasis is placed on resonance electroproduction because transition form factors extracted from electroproduction data provide a keen tool for revealing resonance structure. Abstract Published by the Jagiellonian University 2026 authors