Probing new physics in the laboratory and in space

The Standard Model (SM) of particle physics fails to explain several observed phenomena and is incomplete. In order to resolve this problem, one may extend the SM by adding new particles. However, yet they have not been observed, and currently, the scientific community tries to find a signature that manifests the existence and properties of such particles. This thesis is devoted to exploring the parameter space of Feebly Interacting new physics Particles (FIPs) in a model-independent fashion using two complementary approaches. The first one is searching for FIPs at next-generation accelerator experiments called Intensity Frontier experiments. The second one is constraining the parameter space of FIPs by considering their possible impact on the observables coming from the Early Universe - Big Bang Nucleosynthesis and Cosmic Microwave Background, which are in good agreement with the predictions of the cosmological models with SM particles. They are, therefore, very sensitive to the possible existence of FIPs in the primordial plasma. As a result of the researches constituting this thesis, novel model-independent results, as well as constraints on particular models of FIPs such as Heavy Neutral Leptons, have been obtained in both of these areas.Theoretical Physic

catena-Poly[sodium-di-μ-aqua-sodium-bis[μ-2,2,2-trichloro-N-(dimorpholinophosphoryl)acetamide]]

The title compound, [Na2(C10H16Cl3N3O4P)2(H2O)2]n, can be considered as a two-dimensional coordination polymer in which one-dimensional chains are connected to each other by inter­molecular C—H⋯O hydrogen bonds involving the water mol­ecules. The NaI ion is five-coordinated in a distorted trigonal-bipyramidal geometry. The connection between the two NaI ions is facilitated by the two μ-O atoms of the carbonyl group of the 2,2,2-trichloro-N-(dimorpholino­phosphor­yl)acetamide (CAPh) ligand. A bridging coordination of the CAPh ligand via the carbonyl O atom is observed for the first time. The bridging water mol­ecules form inter­molecular O—H⋯O hydrogen bonds with the O atoms of the morpholine rings and the phosphoryl groups of neighboring CAPh mol­ecules

Dipole portal and neutrinophilic scalars at DUNE revisited: the importance of the high-energy neutrino tail

Theoretical Physic

Constraints from the CHARM experiment on heavy neutral leptons with tau mixing

Theoretical Physic

catena-Poly[neodymium(III)-bis­[μ-N-(dimorpholinophosphor­yl)benzene­sulfonamidato]-sodium(I)-bis­[μ-N-(dimorpholinophosphor­yl)benzene­sulfonamidato]]

The cubic crystal structure of the title compound, [NaNd(C14H21N3O5PS)4]n, is composed of one-dimensional polymeric chains propagating in [100], built up from [Nd(C14H21N3O5PS)4]− anions and sodium cations functioning as linkers. In the complex anion, the Nd3+ ion has an eightfold coordination environment formed by the sulfonyl and phosphoryl O atoms of four bidentate chelating N-(dimorpholinophosphor­yl)benzene­sulfonamidate ligands: the resulting NdO8 polyhedron can be described as inter­mediate between dodeca­hedral and square anti­prismatic. The sodium ion adopts an NaO4 tetra­hedral geometry arising from four monodentate benzene­sulfonamidate ligands. The resulting crystal structure is unusual because it contains substantial voids (800 Å3 per unit cell), within which there is no evidence of included solvent

Sensitivity of the SHiP experiment to Heavy Neutral Leptons

Heavy Neutral Leptons (HNLs) are hypothetical particles predicted by many extensions of the Standard Model. These particles can, among other things, explain the origin of neutrino masses, generate the observed matter-antimatter asymmetry in the Universe and provide a dark matter candidate. The SHiP experiment will be able to search for HNLs produced in decays of heavy mesons and travelling distances ranging between O(50 m) and tens of kilometers before decaying. We present the sensitivity of the SHiP experiment to a number of HNL's benchmark models and provide a way to calculate the SHiP's sensitivity to HNLs for arbitrary patterns of flavour mixings. The corresponding tools and data files are also made publicly available.Theoretical Physic

Bis(N-{bis­[meth­yl(phen­yl)amino]phos­phor­yl}-2,2,2-trichloro­acetamide)di­nitrato­dioxidouranium(VI)

In the title compound, [UO2 L 2(NO3)2] {L = N-{bis­[meth­yl(phen­yl)amino]phosphor­yl}-2,2,2-trichloro­acetamide, C16H17Cl3N3O2P}, the UVI ions are eight-coordinated by axial oxido ligands and six equatorial O atoms from the phosphoryl and nitrate groups in a distorted hexa­gonal–bipyramidal geometry. There are disordered fragments in the two coordinating L ligands: the trichloro­methyl group is rotationally disordered between two orientations [occupancy ratio 0.567 (15):0.433 (15)] in one ligand, and a meth­yl(phen­yl)amine fragment is disordered over two conformations [occupancy ratio 0.60 (4):0.40 (4)] in the other ligand. In the crystal structure, intra­molecular N—H⋯O hydrogen bonds between the amine and nitrate groups are observed

Bis{N-[bis­(pyrrolidin-1-yl)phosphor­yl]-2,2,2-trichloro­acetamide}di­nitrato­dioxidouranium(VI)

The crystal structure of the title compound, [U(NO3)2O2(C10H17Cl3N3O2P)2], is composed of centrosymmetric [UO2(L)2(NO3)2] mol­ecules {L is N-[bis­(pyrrolidin-1-yl)phosphor­yl]-2,2,2-trichloro­acetamide, C10H17Cl3N3O2P}. The UVI ion, located on an inversion center, is eight-coordinated with axial oxido ligands and six equatorial oxygen atoms of the phosphoryl and nitrate groups in a slightly distorted hexa­gonal-bipyramidal geometry. One of the pyrrolidine fragments in the ligand is disordered over two conformation (occupancy ratio 0.58:0.42). Intra­molecular N—H⋯O hydrogen bonds between the amine and nitrate groups are found

Towards the optimal beam dump experiment to search for feebly interacting particles

Theoretical Physic

Light scalar production from Higgs bosons and FASER 2

Theoretical Physic