Karol Kampf
A5036859619- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Black Holes and Theoretical Physics
- Dark Matter and Cosmic Phenomena
- Computational Physics and Python Applications
- Neutrino Physics Research
- Cosmology and Gravitation Theories
- Atomic and Subatomic Physics Research
- Particle Detector Development and Performance
- Particle Accelerators and Free-Electron Lasers
- Noncommutative and Quantum Gravity Theories
- Advanced NMR Techniques and Applications
- Nuclear physics research studies
- Cold Atom Physics and Bose-Einstein Condensates
- Nonlinear Waves and Solitons
- Algebraic structures and combinatorial models
- Radiation Detection and Scintillator Technologies
- Physics of Superconductivity and Magnetism
- Matrix Theory and Algorithms
- Quantum, superfluid, helium dynamics
- Nonlinear Photonic Systems
- Medical Imaging Techniques and Applications
- Homotopy and Cohomology in Algebraic Topology
- Astrophysics and Cosmic Phenomena
Charles University
2016-2025
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati
2017-2024
Roma Tre University
2024
UCLouvain
2022
Istituto Nazionale di Fisica Nucleare, Sezione di Napoli
2022
Centre National de la Recherche Scientifique
2009-2021
Aix-Marseille Université
2009-2021
Université de Toulon
2021
Centre d’Immunologie de Marseille-Luminy
2021
Joint Institute for Nuclear Research
2020
NA62 is a fixed-target experiment at the CERN SPS dedicated to measurements of rare kaon decays. Such measurements, like branching fraction K+ → π+ ν decay, have potential bring significant insights into new physics processes when comparison made with precise theoretical predictions. For this purpose, innovative techniques been developed, in particular, domain low-mass tracking devices. Detector construction spanned several years from 2009 2014. The collaboration started detector...
We derive scalar effective field theories - Lagrangians, symmetries, and all from on-shell scattering amplitudes constructed purely Lorentz invariance, factorization, a fixed power counting order in derivatives, at which vanish the soft limit. These constraints leave free parameters amplitude are coupling constants of well-known theories: Nambu-Goldstone bosons, Dirac-Born-Infeld scalars, Galileons. Moreover, limits imply conditions on Noether current can then be inverted to Lagrangians for...
A bstract The NA62 experiment reports the branching ratio measurement $$ \mathrm{BR}\left({K}^{+}\to {\pi}^{+}\nu \overline{\nu}\right)=\left({10.6}_{-3.4}^{+4.0}\left|{}_{\mathrm{stat}}\right.\pm {0.9}_{\mathrm{syst}}\right)\times {10}^{-11} <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>BR</mml:mi> <mml:mfenced> <mml:mrow> <mml:msup> <mml:mi>K</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:mi>π</mml:mi> <mml:mi>ν</mml:mi> <mml:mover> <mml:mo>¯</mml:mo>...
Recently, Arkani-Hamed proposed the existence of zeros in scattering amplitudes certain quantum field theories including cubic adjoint scalar theory <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>Tr</a:mi><a:mo stretchy="false">(</a:mo><a:msup><a:mi>ϕ</a:mi><a:mn>3</a:mn></a:msup><a:mo stretchy="false">)</a:mo></a:math>, <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi>S</e:mi><e:mi>U</e:mi><e:mo...
We systematically explore the space of scalar effective field theories (EFTs) consistent with a Lorentz invariant and local S-matrix. To do so we define an EFT classification based on four parameters characterizing 1) number derivatives per interaction, 2) soft properties amplitudes, 3) leading valency interactions, 4) spacetime dimension. Carving out allowed EFTs, prove that exceptional EFTs like non-linear sigma model, Dirac-Born-Infeld theory, special Galileon lie precisely boundary...
We derive the first ever on-shell recursion relations applicable to effective field theories. Based solely on factorization and soft behavior of amplitudes, these employ a new rescaling momentum shift construct all tree-level scattering amplitudes in nonlinear sigma model, Dirac-Born-Infeld theory, Galileon. Our results prove that theories with enhanced are constructible.
A search for heavy neutral lepton production in $K^+$ decays using a data sample collected with minimum bias trigger by the NA62 experiment at CERN 2015 is reported. Upper limits $10^{-7}$ to $10^{-6}$ level are established on elements of extended neutrino mixing matrix $|U_{\ell 4}|^2$ ($\ell=e,\mu$) mass range $170-448~{\rm MeV}/c^2$. This improves results from previous searches decays, setting more stringent and extending range.
A search for heavy neutral lepton (N) production in K+→e+N decays using the data sample collected by NA62 experiment at CERN 2017–2018 is reported. Upper limits of extended neutrino mixing matrix element |Ue4|2 are established level 10−9 over most accessible mass range 144–462 MeV/c2, with assumption that lifetime exceeds 50 ns. These improve significantly upon those previous and decay searches. The favoured Big Bang Nucleosynthesis excluded up to a about 340 MeV/c2.
The NA62 experiment at CERN reports searches for $K^+\to\mu^+N$ and $K^+\to\mu^+\nu X$ decays, where $N$ $X$ are massive invisible particles, using the 2016-2018 data set. particle is assumed to be a heavy neutral lepton, results expressed as upper limits of ${\cal O}(10^{-8})$ neutrino mixing parameter $|U_{\mu4}|^2$ masses in range 200-384 MeV/$c^2$ lifetime exceeding 50 ns. considered scalar or vector hidden sector mediator decaying an final state, decay branching fraction 10-370 reported...
Abstract Kaon physics is at a turning point – while the rare-kaon experiments NA62 and KOTO are in full swing, end of their lifetime approaching future experimental landscape needs to be defined. With HIKE, KOTO-II LHCb-Phase-II on table under scrutiny, it very good moment time take stock contemplate about opportunities these theoretical developments provide for particle coming decade beyond. This paper provides compact summary talks discussions from Kaons@CERN 2023 workshop, held September CERN.
Using the large N_C approximation we have constructed most general chiral resonance Lagrangian in odd-intrinsic parity sector that can generate low energy constants up to O(p^6). Integrating out fields these O(p^6) are expressed terms of couplings and masses. The role eta' is discussed its contribution explicitly factorized. basis also calculated two QCD Green functions currents: <VVP> <VAS> found, imposing high constraints, additional relations for couplings. We studied several...
We present a bottom-up construction of vector effective field theories using the infrared structure scattering amplitudes. Our results employ two distinct probes soft kinematics: multiple limits and single after dimensional reduction applicable in four general dimensions, respectively. Both approaches uniquely specify Born-Infeld (BI) model as only theory vectors completely fixed by certain conditions which generalize Adler zero for pions. These properties imply new recursion relations...
The NA62 experiment at the CERN SPS reports first search for $K^+ \rightarrow \pi^+ \nu \bar{\nu}$ using decay-in-flight technique, based on a sample of $1.21\times10^{11}$ $K^+$ decays collected in 2016. single event sensitivity is $3.15\times 10^{-10}$, corresponding to 0.267 Standard Model events. One signal candidate observed while expected background 0.152 This leads an upper limit $14 \times 10^{-10}$ branching ratio 95\% CL.
The results of a search for $\pi^0$ decays to photon and an invisible massive dark at the NA62 experiment CERN SPS are reported. From total $4.12\times10^8$ tagged mesons, no signal is observed. Assuming kinetic-mixing interaction, limits set on coupling ordinary as function mass, improving previous searches in mass range 60--110 MeV/$c^2$. present interpreted terms upper limit branching ratio electro-weak decay $\pi^0 \to \gamma \nu \overline{\nu}$, current by more than three orders magnitude.
A bstract The NA62 experiment at the CERN SPS reports a study of sample 4 × 10 9 tagged π 0 mesons from K + → ( γ ), searching for decay to invisible particles. No signal is observed in excess expected background fluctuations. An upper limit . − set on branching ratio 90% confidence level, improving previous results by factor 60. This result can also be interpreted as model- independent X , where particle escaping detection with mass range 0.110–0.155 GeV /c 2 and rest lifetime greater than...
The corrections induced by light quark masses to the current algebra result for ${\ensuremath{\pi}}^{0}$ lifetime are reexamined. We consider next-to-next-to-leading order and we compute all one-loop two-loop diagrams which contribute decay amplitude at this in two-flavor chiral expansion. show that is renormalizable, as Weinberg consistency conditions satisfied. find logarithms present unlike case next-to-leading order. could be used conjunction with lattice QCD simulations, feasibility of...
Because of their small electromagnetic corrections, the isospin-breaking decays $\eta\to3\pi$ seem to be good candidates for extracting parameters $ (m_d-m_u)$. This task is unfortunately complicated by large chiral corrections and discrepancy between experimentally measured values Dalitz describing energy dependence amplitudes these those predicted from perturbation theory. We present two methods based on an analytic dispersive representation that use information NNLO result one measurement...
A bstract search for the K + → π X decay, where is a long-lived feebly interacting particle, performed through an interpretation of $$ {\pi}^{+}\nu \overline{\nu} <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>π</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mi>ν</mml:mi> <mml:mover> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> analysis data collected in 2017 by NA62 experiment at CERN. Two ranges masses, 0–110 MeV /c 2 and 154–260 , lifetimes above 100 ps are...
A sample of 3984 candidates the K+→π+γγ decay, with an estimated background 291±14 events, was collected by NA62 experiment at CERN during 2017–2018. In order to describe observed di-photon mass spectrum, next-to-leading contribution in chiral perturbation theory found be necessary. The decay branching ratio full kinematic range is measured (9.61±0.17)×10−7. first search for production and prompt axion-like particle gluon coupling process K+→π+a, a→γγ also reported.
In this paper we discuss a generalization of the Adler zero to loop integrands in planar limit <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>S</a:mi><a:mi>U</a:mi><a:mo stretchy="false">(</a:mo><a:mi>N</a:mi><a:mo stretchy="false">)</a:mo></a:math> nonlinear sigma model (NLSM). The for is violated starting at two-loop order and only recovered after integration. Here propose soft theorem satisfied by with any number loops legs. This requires NLSM an off shell...
We study dualities of the general Galileon theory in d dimensions terms coordinate transformations on coset space corresponding to spontaneously broken group. The most duality transformation is found be determined uniquely up four free parameters and under compositions these form a group which can identified with GL(2,R). This represents unified framework for all now known dualities. discuss representation this using concrete examples we illustrate its applicability both classical quantum level.
It is well-known that the standard BCFW construction cannot be used for on-shell amplitudes in effective field theories due to bad behavior large shifts. We show how solve this problem case of SU(N) non-linear sigma model, i.e. non-renormalizable model with infinite number interaction vertices, using scaling properties semi-on-shell currents, and we present new recursion relations all tree-level theory.
The NA62 experiment at CERN reports a search for the lepton number violating decays K+→π−e+e+ and K+→π−μ+μ+ using data sample collected in 2017. No signals are observed, upper limits on branching fractions of these 2.2×10−10 4.2×10−11 obtained, respectively, 90% confidence level. These improve previously reported measurements by factors 3 2, respectively.
We have recalculated the Mikaelian and Smith radiative corrections to Dalitz decay ${\ensuremath{\pi}}^{0}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}\ensuremath{\gamma}$ beyond soft-photon approximation, i.e. over whole range of plot with no restrictions on photon. In contrast previous calculations, we did not neglect terms order higher than $\mathcal{O}({m}^{2})$ also included one-photon irreducible contribution at one-loop level virtual muon loop contribution. The results can then...