Orlando Panella

Orlando Panella
INFN - Istituto Nazionale di Fisica Nucleare | INFN · Perugia

Doctor of Philosophy

About

112
Publications
5,868
Reads
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1,012
Citations
Additional affiliations
May 1995 - present
INFN - Istituto Nazionale di Fisica Nucleare
Position
  • Senior Researcher
Description
  • High Energy Theory. Physics beyond the Standard Model at the LHC and future accelerators.
January 1993 - May 1995
Laboratoire de Physique Corpusculaire
Position
  • College de France

Publications

Publications (112)
Preprint
Full-text available
We study the quantum backflow problem of a relativistic charged Dirac fermion constrained to move on a ring of radius $R$. Using the relativistic current operator we compute the probability flux through a generic time interval to show emergence of quantum backflow. We also discuss the limiting case when the particle moves along a line.
Preprint
Composite-fermion models predict excited quarks and leptons with mass scales which can potentially be observed at high-energy colliders like the LHC; the most recent exclusion limits from the CMS and ATLAS Collaborations corner excited-fermion masses and the compositeness scale to the multi-TeV range. At the same time, hypothetical composite Majora...
Article
Full-text available
In this paper, we present the one-loop radiative corrections to the electroweak precision observable Δρ coming from the IW=1 multiplet excited leptons. We have calculated the couplings of the exotic lepton triplet to the vector bosons and ordinary leptons using the effective Lagrangian approach. These couplings are then used to estimate the excited...
Article
We study the quantum backflow problem in the noncommutative plane. In particular, we have considered a charged particle with and without an oscillator interaction with noncommuting momentum operators and examined angular momentum backflow in each case and how they differ from each other. We also propose a probability associated with the occurrence...
Preprint
We study the quantum backflow problem in the noncommutative plane. In particular, we have considered a charged particle with and without an oscillator interaction with noncommuting momentum operators and examined angular momentum backflow in each case and how they differ from each other. We also propose a probability associated with the occurence o...
Preprint
In this paper, we present the one-loop radiative corrections to the electroweak precision observable $\Delta \rho$ coming from the $I_W=1$ multiplet excited leptons. We have calculated the couplings of the exotic lepton triplet to the vector bosons and ordinary leptons using effective Lagrangian approach. These couplings are then used to estimate t...
Article
Full-text available
We report on the status of efforts to improve the reinterpretation of searches and measurements at the LHC in terms of models for new physics, in the context of the LHC Reinterpretation Forum. We detail current experimental offerings in direct searches for new particles, measurements, technical implementations and Open Data, and provide a set of re...
Article
Full-text available
This article gives an account of a theoretical research subdivided into three parts. The first stage recalls the theorem of large numbers and the theorem a single number which demonstrate how the frequentist and the subjective models of probability can be used according to distinct assumptions. Based on these achievements, the second stage describe...
Article
Full-text available
A new physics scenario shows that four-fermion operators of Nambu-Jona-Lasinio (NJL) type have a strong-coupling UV fixed point, where composite fermions F (bosons \(\Pi \)) form as bound states of three (two) SM elementary fermions and they couple to their constituents via effective contact interactions at the composite scale \(\Lambda \approx {{{...
Preprint
Full-text available
We report on the status of efforts to improve the reinterpretation of searches and measurements at the LHC in terms of models for new physics, in the context of the LHC Reinterpretation Forum. We detail current experimental offerings in direct searches for new particles, measurements, technical implementations and Open Data, and provide a set of re...
Article
Full-text available
We report on the status of efforts to improve the reinterpretation of searches and measurements at the LHC in terms of models for new physics, in the context of the LHC Reinterpretation Forum. We detail current experimental offerings in direct searches for new particles, measurements, technical implementations and Open Data, and provide a set of re...
Article
Full-text available
We present the derivation of the Casimir-Polder interactions mediated by a massive photon between two neutral systems described in terms of their atomic polarizability tensors. We find a compact expression for the leading term at large distances between the two systems. Our result reduces, in the massless photon limit, to the standard Casimir-Polde...
Article
Full-text available
We use the extension problem proposed by Caffarelli and Silvestre to study the quantization of a scalar nonlocal quantum field theory built out of the fractional Laplacian. We show that the quantum behavior of such a nonlocal field theory in d dimensions can be described in terms of a local action in d+1 dimensions which can be quantized using the...
Preprint
Full-text available
We present the derivation of the Casimir-Polder interactions mediated by a massive photon between two neutral systems described in terms of their atomic polarizability tensors. We find a compact expression for the leading term at large distances between the two systems. Our result reduces, in the mass-less photon limit, to the standard Casimir-Pold...
Article
Full-text available
Numerical results for the partial wave unitarity bounds on the parameter space (Λ,M) of dimension-6 effective operators of a composite scenario presented in Biondini et al. (2019) [1] are revised. Figs. 2-5 and Table 1 are to be replaced by the following corresponding figures and table. We briefly comment on the impact on the conclusions presented...
Preprint
Full-text available
We use the extension problem proposed by Caffarelli and Silvestre to study the quantization of a scalar nonlocal quantum field theory built out of the fractional Laplacian. We show that the quantum behavior of such a nonlocal field theory in $d$-dimensions can be described in terms of a local action in $d+1$ dimensions which can be quantized using...
Article
Full-text available
In this paper we present the partial wave unitarity bound in the parameter space of dimension-5 and dimension-6 effective operators that arise in a compositeness scenario. These are routinely used in experimental searches at the LHC to constraint contact and gauge interactions between ordinary Standard Model fermions and excited (composite) states...
Preprint
In this paper we present the partial wave unitarity bound in the parameter space of dimension-5 and dimension-6 effective operators that arise in a compositeness scenario. These are routinely used in experimental searches at the LHC to constraint contact and gauge interactions between ordinary Standard Model fermions and excited (composite) states...
Preprint
Full-text available
This is the third out of five chapters of the final report [1] of the Workshop on Physics at HL-LHC, and perspectives on HE-LHC [2]. It is devoted to the study of the potential, in the search for Beyond the Standard Model (BSM) physics, of the High Luminosity (HL) phase of the LHC, defined as $3$ ab$^{-1}$ of data taken at a centre-of-mass energy o...
Preprint
Within a mirror type assignment for the excited composite fermions the neutrino mass term is built up from a Dirac mass, $m_*$, which gives the mass of charged lepton component of the $SU(2)$, right-handed, doublet, and a Majorana mass, $m_L$, for the left-handed component (singlet) of the excited neutrino. The mass matrix is diagonalized leading t...
Preprint
A new physics scenario shows that four-fermion operators have a strong-coupling UV fixed point, where composite fermions $F$ (bosons $\Pi$) form as bound states of three (two) SM elementary fermions and they couple to their constituents via effective contact interactions at the composite scale $\Lambda \approx {\cal O} $(TeV). We present a phenomen...
Article
In this paper we present exact solutions of the Dirac equation on the non-commutative plane in the presence of crossed electric and magnetic fields. In the standard commutative plane such a system is known to exhibit contraction of Landau levels when the electric field approaches a critical value. In the present case we find exact solutions in term...
Preprint
Full-text available
In this paper we present exact solutions of the Dirac equation on the non-commutative plane in the presence of crossed electric and magnetic fields. In the standard commutative plane such a system is known to exhibit contraction of Landau levels when the electric field approaches a critical value. In the present case we find exact solutions in term...
Article
Full-text available
A search for physics beyond the standard model in the final state with two same-flavour leptons (electrons or muons) and two quarks produced in proton–proton collisions at s=13TeV is presented. The data were recorded by the CMS experiment at the CERN LHC and correspond to an integrated luminosity of 2.3fb−1. The observed data are in good agreement...
Article
Full-text available
The Dirac oscillator in a homogenous magnetic field exhibits a chirality phase transition at a particular (critical) value of the magnetic field. Recently, this system has also been shown to be exactly solvable in the context of noncommutative quantum mechanics featuring the interesting phenomenon of re-entrant phase transitions. In this work we pr...
Article
Full-text available
In this paper we present the un-Casimir effect, namely the study of the Casimir energy in the presence of an unparticle component in addition to the electromagnetic field contribution. The distinctive feature of the un-Casimir effect is a fractalization of metallic plates. This result emerges through a new dependence of the Casimir energy on the pl...
Article
Full-text available
We consider the production at the LHC of exotic composite quarks of charge $Q=+(5/3) e$ and $Q=-(4/3) e$. Such states are predicted in composite models of higher isospin multiplets ($I_W=1$ or $I_W=3/2$). Given their exotic charges (such as $5/3$), their decays proceed through the electroweak interactions. We compute decay widths and rates for reso...
Article
Full-text available
It is shown that bound state solutions of the one dimensional Bogoliubov-de Gennes (BdG) equation may exist when the Fermi velocity becomes dependent on the space coordinate. The existence of bound states in continuum (BIC) like solutions has also been confirmed both in the normal phase as well as in the super-conducting phase. We also show that a...
Article
It is shown that bound state solutions of the one dimensional Bogoliubov-de Gennes (BdG) equation may exist when the Fermi velocity becomes dependent on the space coordinate. The existence of bound states in continuum (BIC) like solutions has also been confirmed both in the normal phase as well as in the super-conducting phase. We also show that a...
Article
Full-text available
We discuss the (2+1)-dimensional Dirac oscillator in a magnetic field in non commutative quantum mechanics. The system is known to be characterised by a left right- chiral phase transition in ordinary Quantum mechanics. We show that the momentum noncommutativity shifts the know phase transition while the space non commutativity introduces a new rig...
Article
Full-text available
Motivated by the recent observation of an excess in the $eejj$ channel by the CMS collaboration we investigate the search for heavy Majorana neutrinos stemming from a composite model scenario at the upcoming LHC Run II at a center of mass energy of 13 TeV. While previous studies of the composite Majorana neutrino were focussed on gauge interactions...
Article
Full-text available
We obtain exact solutions of the (2+1) dimensional Dirac oscillator in a homogeneous magnetic field within the Anti-Snyder modified uncertainty relation characterized by a momentum cut-off ($p\leq p_{\text{max}}=1/ \sqrt{\beta}$). In ordinary quantum mechanics ($\beta\to 0$) this system is known to have a single left-right chiral quantum phase tran...
Data
Full-text available
We obtain exact solutions of the (2+1) dimensional Dirac oscillator in a homogeneous magnetic field within a minimal length ($\Delta x_0=\hbar \sqrt{\beta}$), or generalised uncertainty principle (GUP) scenario. This system in ordinary quantum mechanics has a single left-right chiral quantum phase transition (QPT). We show that a non zero minimal l...
Article
Full-text available
Doubly charged excited leptons determine a possible signature for physics beyond the standard model at the present Large Hadron Collider. These exotic states are introduced in extended isospin multiplets and they can be treated either within gauge or contact effective interactions or a mixture of those. In this paper we study the production and the...
Article
Full-text available
We obtain exact solutions of the (2+1) dimensional Dirac oscillator in a homogeneous magnetic field within a minimal length ($\Delta x_0=\hbar \sqrt{\beta}$), or generalised uncertainty principle (GUP) scenario. This system in ordinary quantum mechanics has a single left-right chiral quantum phase transition (QPT). We show that a non zero minimal l...
Article
Full-text available
We study the (2+1) dimensional Dirac oscillator in a homogeneous magnetic field in the non-commutative plane. It is shown that the effect of non-commutativity is twofold: $i$) momentum non commuting coordinates simply shift the critical value ($B_{\text{cr}}$) of the magnetic field at which the well known left-right chiral quantum phase transition...
Article
Full-text available
We study the production of doubly charged excited leptons at the LHC. These exotic states are predicted in extended weak isospin composite models. A recent analysis of such exotic states was based on a pure gauge model with magnetic type interactions. We include here the mechanism of contact interactions and show that this turns out to dominate the...
Article
Full-text available
We consider $(2+1)$ dimensional massless Dirac equation in the presence of complex vector potentials. It is shown that such vector potentials (leading to complex magnetic fields) can produce bound states and the Dirac Hamiltonians are $\eta$-pseudo Hermitian. Some examples have been explicitly worked out.
Article
Full-text available
The production at the LHC of exotic excited leptons of charge $Q = +2e$ is considered. Such states are predicted in composite models with extended isospin multiplets ($I_{W}=1$ and $I_{W}=3/2$). The coupling among these doubly charged leptons and Standard Model fermions may occurs either via gauge or contact interactions. In the former case the dec...
Article
Full-text available
In this paper we present the un-Casimir effect, namely the study of the Casimir energy related to the presence of an un-particle component in addition to the electromagnetic field contribution. We derive this result by considering modifications of the Feynmann propagator in the unparticle sector. The contribution of unparticles turns out to be the...
Article
Full-text available
We study the (2+1) dimensional Dirac equation in an homogeneous magnetic field (relativistic Landau problem) within a minimal length, or generalized uncertainty principle -GUP-, scenario. We derive exact solutions for a given explicit representation of the GUP and provide expressions of the wave functions in the momentum representation. We find tha...
Article
We study generalized Dirac oscillators with complex interactions in $(1+1)$ dimensions. It is shown that for the choice of interactions considered here, the Dirac Hamiltonians are $\eta$ pseudo Hermitian with respect to certain metric operators $\eta$. Exact solutions of the generalized Dirac Oscillator for some choices of the interactions have als...
Article
Full-text available
We introduce new observables for the study of the inclusive same sign dileptons production at LHC which are built out of ratios of the observed number of same-sign dileptons, both with same $N(\ell,\ell)$ and different flavor $N(\ell,\ell')$. As a case study we apply them to the stau coannihilation region of the constrained minimal supersymmetric s...
Article
We examine the one dimensional Dirac equation with modulated or position dependent velocity. In particular, it is shown that using suitable velocity profiles it is possible to create bound state in continuum (BIC) like, as well as, discrete energy bound state solutions.
Article
Full-text available
We study the corrections to the Casimir effect in the classical geometry of two parallel metallic plates, separated by a distance a, due to the presence of a minimal length (ℏ√β) arising from quantum mechanical models based on a generalized uncertainty principle (GUP). The approach for the quantization of the electromagnetic field is based on proje...
Article
Full-text available
The standard model of strong interactions invokes the quantum chromodynamics (QCD) of quarks and gluons interacting within a fluid. At sufficiently small length scales, the effective interactions between the color charged particles within the fluid are thought to be weak. Short distance asymptotic freedom provides the perturbation theory basis for...
Article
Full-text available
The well-known Klein paradox for the relativistic Dirac wave equation consists in the computation of possible "negative probabilities" induced by certain potentials in some regimes of energy. The paradox may be resolved by employing the notion of electron–positron pair production in which the number of electrons present in a process can increase. T...
Article
Full-text available
We consider the production at the LHC of exotic composite leptons of charge Q=+2e. Such states are allowed in composite models which contain extended isospin multiplets (Iw=1 and Iw=3/2). These doubly charged leptons couple with Standard Model [SM] fermions via gauge interactions, thereby delineating and restricting their possible decay channels. W...
Article
Full-text available
We revise the impact of internal bremsstrahlung photons in the context of the constrained minimal supersymmetric standard model on gamma-ray dark matter annihilation searches. As an example, we review the gamma-ray dark matter detection prospects from Draco dwarf spheroidal galaxy at the MAGIC stereoscopic system and the CTA project. We find that f...
Article
Full-text available
We study the formation and detection at the next linear $e^+e^-$ collider of bound states of level-1 quark Kaluza-Klein excitations ${\cal B}_{KK}$ within a scenario of universal extra-dimensions (UED). Comment: 11 pages, 2 figures. Contributed paper to the proceedings of LC09: e+e- physics at the TeV scale and the Dark Matter connection. 21-24 Sep...
Article
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For a bound state internal wave function respecting parity symmetry, it can be rigorously argued that the mean electric dipole moment must be strictly zero. Thus, both the neutron, viewed as a bound state of three quarks, and the water molecule, viewed as a bound state of ten electrons two protons and an oxygen nucleus, both have zero mean electric...
Article
Full-text available
We present a detailed study of the effect of internal bremsstrahlung photons in the context of the minimal supersymmetric standard models and their impact on gamma-ray dark matter annihilation searches. We find that although this effect has to be included for the correct evaluation of fluxes of high energy photons from neutralino annihilation, its...
Article
Full-text available
We examine the prospects for the detection of Higgs mediated lepton flavor violation at LHC and at a photon collider in the minimal supersymmetric standard model with large lepton flavor violating mass insertions in the $\mu-\tau$ sector constraining the parameter space with several experimental bounds. We find rates probably too small to be observ...
Article
Full-text available
We study the one-dimensional Dirac equation in the framework of a position dependent mass under the action of a Woods-Saxon external potential. We find that constraining appropriately the mass function it is possible to obtain a solution of the problem in terms of the hypergeometric function. The mass function for which this turns out to be possibl...
Article
Full-text available
We consider the minimal supersymmetric standard model within a scenario of large $\tan\beta$ and heavy squarks and gluinos, with masses of the heavy neutral Higgs bosons below the TeV scale. We allow for the presence of a large, model independent, source of lepton flavor violation (LFV) in the slepton mass matrix in the $\tau-\mu$ sector by the mas...
Article
Full-text available
The process gamma gamma \to mu tau b bbar is studied in the minimal supersymmetric standard model within a large tan_beta scenario imposing on the parameter space present direct and indirect constraints from B physics and rare LFV tau-decays. At a photon collider based on an e+e- linear collider with a center of mass energy of 800 GeV with the para...
Article
The standard model of strong interactions invokes the quantum chromodynamics (QCD) of quarks and gluons interacting within a fluid. At sufficiently small length scales, the effective interactions between the color charged particles within the fluid are thought to be weak. Short distance asymptotic freedom provides the perturbation theory basis for...
Article
Full-text available
We study a new signature of lepton flavor violation (LFV) at the Photon Collider (PC) within Supersymmetric (SUSY) theories. We consider the minimal supersymmetric standard model within a large $\tan\beta$ scenario with all superpartner masses in the ${\cal O}$(TeV) while the heavy Higgs bosons masses lie below the TeV and develop sizable loop indu...
Article
Full-text available
It is shown that in reaction gammagamma-->l+l-+nu's at s>200GeV with polarized photons, large and well observable differences arise in the distribution of positive and negative charged leptons (l=mu±, e±) (charge asymmetry). The modification due to the contribution of the cascade processes with intermediate tau lepton in gammagamma-->W±l-/++nu's re...
Article
Full-text available
We study the formation and detection at the next linear e^+e^- collider of bound states of level-1 quark Kaluza-Klein excitations B_KK within a scenario of universal extra-dimensions (UED). The interactions of such Kaluza-Klein excitations are modeled by an alpha_s driven Coulomb potential. In order to obtain the threshold cross-section, we employ...
Article
Full-text available
No consensus seems to exist as to what constitutes a measurement which is still considered somewhat mysterious in many respects in quantum mechanics. At successive stages mathematical theory of measure, metrology and measurement theory tried to systematize this field but significant questions remain open about the nature of measurement, about the...
Article
Full-text available
Generalized uncertainty relations are known to provide a minimal length $\hbar\sqrt{\beta}$. The effect of such minimal length in the Casimir-Polder interactions between neutral atoms (molecules) is studied. The first order correction term in the minimal uncertainty parameter is derived and found to describe an attractive potential scaling as $r^{-...
Article
The momentum distributions of positively and negatively charged leptons (ℓ± = μ±, e±) in the reactions of type γγ → ℓ+ℓ + Nv, γγ → W±ℓ± + Nv at √s > 200 GeV with polarized photons demonstrates a considerable charge asymmetry. We discuss the influence of photon non-monochromaticity on this effect and its dependence on transverse momentum, which will...
Article
Full-text available
The lepton flavour violating (LFV) reactions {gamma gamma to ell ell '} ({ell ,ell '= e, mu ,tau }, ell not =ell ') which arise at the one loop order of perturbation theory are studied at energies of interest for the gamma gamma option of the future ILC. The LFV mechanism is provided by low energy R-conserving SUSY with non diagonal slepton mass ma...
Article
It is shown that the difference in the momentum distributions of positively (μ+, e+) and negatively (μ-, e -) charged leptous in the reactions of type γγ → μ+μ- + Nv, γγ → W± μ ±+ Nv at √s > 200 GeV with polarized photons demonstrates a considerable charge asymmetry of muon distributions, sensitive to New Physics effects. Contribution of processes...
Conference Paper
It is shown that the difference in the momentum distributions of positively (mu(+), e(+)) and negatively (mu(-), e(-)) charged leptons in the reactions of type gamma gamma -> mu(+)y(-) + N nu, gamma gamma -> W-+/-mu(-/+) + N nu at root s > 200 GeV with polarized photons demonstrates a considerable charge asymmetry of muon distributions, sensitive t...