SearcharxivSearch

arXiv subjects

Victor Ilisie

Publications and source records attributed to Victor Ilisie.

13 recordsLinked to original sources

Sensitivity of polaron-molecule observables to MDR/GUP-like ultraviolet deformations at low energies via quantum computing

We show that impurity many-body observables can display enhanced sensitivity to ultraviolet deformations of generalized-uncertainty-principle and modified-dispersion-relation type at accessible energy scales. Using a deformed polaron-molecule Hamiltonian constructed to preserve the infrared sector, we quantify the impact of such deformations on spectral and Ramsey observables and implement the corresponding dynamics in a controlled quantum computing setting. We identify regimes near the polaron-molecule crossover where small ultraviolet deformations are strongly amplified, leading to experimentally resolvable changes in quasiparticle properties and spectral response. Our results establish a concrete sensitivity-based route to low-energy quantum-gravity phenomenology in a well-defined many-body platform and delimit the validity of the effective description. Furthermore, we report experimental validation on the QRed superconducting quantum processor (BSC-CNS).

quant-ph

Generalized Uncertainty Principle as a Mechanism for CP Violation

Within quantum electrodynamics we show that the Generalized Uncertainty Principle induces higher-derivative corrections that promote the topological invariant $F_{\mu\nu}\,\widetilde F^{\mu\nu}$ to the dynamical, non-topological operator $\partial^\lambda F_{\mu\nu}\,\partial_\lambda \widetilde F^{\mu\nu}$. We explore the resulting phenomenology, focusing on the generation of electric dipole moments. Our findings open a new low-energy window for testing quantum-gravity scenarios through precision measurements of charge-parity violation.

hep-ph

The Generalized Uncertainty Principle. New Bounds and Trends

The Heisenberg uncertainty principle is one of the fundamental pillars of quantum mechanics and quantum field theory. It is normally introduced by postulating the commutation relations $[\hat{x}^i, \hat{p}^j] = i\hbar \delta^{ij}$. However, as suggested by some quantum gravity models and string theory, this basic principle no longer holds true in the presence of a minimal length, possible the Plank length, and modifications of the commutation have been proposed i.e., of the form $[\hat{x}^\mu, \hat{p}^\nu ] = -i\hbar(1 + \beta_0 \, \hat{p}^2/\Lambda^2 )\eta^{\mu\nu}$(plus possible additional terms). In this work we will consider the previous modified uncertainty principle in terms of an effective field theory, comment upon some theoretical subtleties that are often overlooked in the literature, and constrain, for the first time, the $\Lambda$ scale with the Compton high-energy experimental data. Our findings suggest that high-energy experiments are potentially sensitive to these corrections and could serve as an effective framework for probing possible violations of the Heisenberg uncertainty principle

hep-ph

Non-metricity signatures on the Higgs boson signal strengths at the LHC

In this work we study the high-energy Higgs boson phenomenology associated to the non-metricity scale $Λ_Q$ at the LHC. Non-metricity is present in more generic non-Riemannian geometries describing gravity beyond General Relativity and exhibits nice features in astronomy and cosmology, and it can be analysed perturbatively. Using effective field theory tools, we calculate the new physics contributions to the one-loop $H\toγγ$ and $gg\to H$ processes and, together with previous bounds from Compton scattering, we obtain relevant constraints and correlations in the model's parameter space. This can help us take a step further, and no longer associate gravitational effects uniquely to astronomical phenomena, and to start analysing these effects by means of high energy experiments. In turn, this could also help us get a better grasp at quantum phenomena associated to gravity.

hep-ph

Fingerprinting the presence of extra scalars in the $h \to Vff'$ forward-backward asymmetry

In this work we analyse the forward-backward asymmetry of the $h\to Vff'$ decay in the Aligned two-Higgs Doublet Model. The Standard Model prediction for this asymmetry for $V=W$ is small, as it suffers from Yukawa suppression and is absent for $V=Z$. This does not necessarily have to hold true in the Aligned model where these contributions can in principle be re-enhanced through the independent alignment factors $ς_f$. In this analysis we conclude that, due to the additional contributions corresponding to the Aligned two-Higgs Doublet Model together with extra sources of CP-violation for the $V=Z$ channel, the Standard Model predictions can be significantly modified in a great region of the parameter space. These deviations, that could be potentially measured at the High Luminosity LHC or future Higgs factories, would be a clear signal of new physics, and would shed new light on the possible extensions of the Standard Model and new sources of CP-violation.

hep-ph

Characterization of TOF-PET Detectors Based on Monolithic Blocks and ASIC-Readout

The aim of this work is to show the potential capabilities of monolithic crystals coupled to large SiPM arrays, to be considered as detector blocks for PET scanners enabling Time Of Flight (TOF) capabilities. Monolithic blocks allow one to decode the 3D photon impact position. This approach, along with TOF information, can be of high interest in clinical Positron emission tomography (PET) applications where a typical ring configuration is used. In this manuscript, we evaluate an ASIC- based readout for digitizing all signals coming from analog photosensors. Validation results with one-to-one coupling resulted in a Coincidence Time Resolution (CTR) of 202 ps FWHM. Providing timing resolution when using detectors based on monolithic crystals is however challenging. The wide distribution of scintillation light on the photosensors causes a poor SNR, which makes the system sensible to false triggering and to time walk errors. In this direction, we present a calibration method, designed to correct all recorded timestamps and also to compensate variations in time-paths among all channels. Thereafter, a CTR improvement nearing 45% is observed for all measurements. Moreover, we show a novel approach that describes the use of averaging methods to assign a single timestamp to each gamma impact. This approach results in a further improvement of the CTR in the range of 100 ps FWHM, reaching a time resolution of 585 ps FWHM when using a large 50x50x10 mm3 LYSO scintillator coupled to an 8x8 SiPM (6x6 mm2) array. These pilot studies show detector capabilities regarding TOF information when using monolithic scintillators.

physics.ins-det

New Barr-Zee contributions to $\mathbf{(g-2)_μ}$ in two-Higgs-doublet models

We study the contribution of new sets of two-loop Barr-Zee type diagrams to the anomalous magnetic moment of the muon within the two-Higgs-doublet model framework. We show that some of these contributions can be quite sizeable for a large region of the parameter space and can significantly reduce, and in some cases even explain, the discrepancy between the theoretical prediction and the experimentally measured value of this observable. Analytical expressions are given for all the calculations performed in this work.

hep-ph

Low-mass fermiophobic charged Higgs phenomenology in two-Higgs-doublet models

After the recent discovery of a Higgs-like boson, the possibility of an enlarged scalar sector arises as a natural question. Experimental searches for charged scalars have been already performed with negative results. We analyze the phenomenology associated with a fermiophobic charged Higgs (it does not couple to fermions at tree level), in two-Higgs-doublet models. All present experimental bounds are evaded trivially in this case, and one needs to consider other decay and production channels. We study the associated production of a charged Higgs with either a $W$ or a neutral scalar boson, and the relevant decays for a light fermiophobic charged Higgs. The interesting features of this scenario should result encouraging for the LHC collaborations to perform searches for such a particle.

hep-ph

Bounds on neutral and charged Higgs from the LHC

After the discovery of a Standard Model-like boson with mass of about 125 GeV the possibility of an enlarged scalar sector arises naturally. Here we present the current status of the phenomenology of the two-Higgs-doublet models with a special focus on the charged Higgs sector. If one considers a fermiophobic charged Higgs (it does not couple to fermions at tree level), all present experimental bounds are evaded trivially, therefore one needs to consider other decay and production channels. In this work we also present some of the interesting features of this specific scenario.

hep-ph

Towards a general analysis of LHC data within two-Higgs-doublet models

The data accumulated so far confirm the Higgs-like nature of the new boson discovered at the LHC. The Standard Model Higgs hypothesis is compatible with the collider results and no significant deviations from the Standard Model have been observed neither in the flavour sector nor in electroweak precision observables. We update the LHC and Tevatron constraints on CP-conserving two-Higgs-doublet models without tree-level flavour-changing neutral currents. While the relative sign between the top Yukawa and the gauge coupling of the 126 GeV Higgs is found be the same as in the SM, at 90% CL, there is a sign degeneracy in the determination of its bottom and tau Yukawa couplings. This results in several disjoint allowed regions in the parameter space. We show how generic sum rules governing the scalar couplings determine the properties of the additional Higgs bosons in the different allowed regions. The role of electroweak precision observables, low-energy flavour constraints and LHC searches for additional scalars to further restrict the available parameter space is also discussed.

hep-ph

Constraining the two-Higgs doublet models with the LHC data

The recent discovery of a Standard Model-like boson with mass of about 126 GeV seems to be the first direct information on the electroweak symmetry breaking mechanism. Using the available experimental data from the LHC and Tevatron we study the implications on the parameter space of the Two-Higgs Doublet Model extension of the Standard Model. The generic structure of the Aligned Two-Higgs Doublet model is imposed in the Yukawa sector; also the models with discrete $\mathcal{Z}_2$ symmetries are analyzed.

hep-ph

LHC constraints on two-Higgs doublet models

A new Higgs-like boson with mass around 126 GeV has recently been discovered at the LHC. The available data on this new particle is analyzed within the context of two-Higgs doublet models without tree-level flavour-changing neutral currents. Keeping the generic Yukawa structure of the Aligned Two-Higgs Doublet Model framework, we study the implications of the LHC data on the allowed scalar spectrum. We analyze both the CP-violating and CP-conserving cases, and a few particular limits with a reduced number of free parameters, such as the usual models based on discrete ${\cal Z}_2$ symmetries.

hep-ph

QCD exotics versus a Standard Model Higgs

The present collider data put severe constraints on any type of new strongly-interacting particle coupling to the Higgs boson. We analyze the phenomenological limits on exotic quarks belonging to non-triplet SU(3)_C representations and their implications on Higgs searches. The discovery of the Standard Model Higgs, in the experimentally allowed mass range, would exclude the presence of exotic quarks coupling to it. Thus, such QCD particles could only exist provided that their masses do not originate in the SM Higgs mechanism.

hep-ph