arXiv subjects

Adam Smetana

Publications and source records attributed to Adam Smetana.

11 recordsLinked to original sources

arXiv2026

Spontaneous BRST symmetry breaking in infrared QCD

We present a novel proposal for the effective Lagrangian of the low-energy Yang--Mills quantum field theory. The proposed effective Lagrangian exhibits the spontaneous BRST symmetry breaking. We built the Fujikawa model that we couple to the Yang--Mills elementary field sector, motivated by the analogy with Chiral Quark Model. We interpret the Fujikawa fields as effective fields composite of the elementary gluon and ghost fields. In order to justify the existence of two massless Nambu--Goldstone modes among the Fujikawa fields, we require not only the BRST but also the anti-BRST invariance of the effective Lagrangian, both to be spontaneously broken. The most striking consequence of that is the emergence of the effective gluon and ghost masses. We reproduce the Curci--Ferrari model as a special case of our effective model upon the spontaneous BRST symmetry breaking. In order to reproduce also the non-nilpotent modified BRST symmetry, characteristic for the Curci--Ferrari model, we modify our effective Lagrangian to be invariant with respect to the extended-BRST symmetry, which mixes the elementary and Fujikawa field sectors, and which is nilpotent. The Curci--Ferrari is reproduced by the elementary field sector of the resulting Lagrangian. The remaining Fujikawa's field dependent terms guarantee the underlying nilpotent extended-BRST symmetry, which is now hidden in the sense of the spontaneous symmetry breaking.

hep-th↗

arXiv2022

Towards interferometry of neutrino electromagnetism

It is predicted within the Standard Model of elementary particles that asymmetric neutrino environments cause rotation of linear polarization of electromagnetic wave -- the birefringence. We demonstrate that this effect is strongly enhanced if additionally the photon is propagating through refractive medium, which effectively increases the photon exposure to the neutrino medium. Our estimate for infrared laser beam in $1\,\mathrm{m}$ long optical fiber exposed to reactor anti-neutrino flux results in linear polarization rotation by the angle $\sim4.6\times10^{-39}\,\mathrm{rad}$. We also derive the proper dependence of the effect on the angle between the directions of photon and neutrino propagation in the laboratory frame. For that purpose we derive the correct form of the basis of polarization four-vectors, which differs from the one widely used in literature. We also estimate the sub-leading optical effect of the neutrino medium due to the neutrino dipole magnetic moment, in terms of a variation of the refractive index and its angular dependence. A rough monochromatic approximation points towards the existence of a resonant enhancement of the effect.

hep-ph↗

arXiv2020

Electroweak $SU(2)_L \times U(1)_Y$ model with strong spontaneously fermion-mass-generating gauge dynamics

Higgs sector of the Standard model (SM) is replaced by quantum flavor dynamics (QFD), the gauged flavor $SU(3)_f$ symmetry with scale $\Lambda$. Anomaly freedom requires addition of three $\nu_R$. The approximate QFD Schwinger-Dyson equation for the Euclidean infrared fermion self-energies $\Sigma_f(p^2)$ has the spontaneous-chiral-symmetry-breaking solutions ideal for seesaw: (1) $\Sigma_f(p^2)=M_{fR}^2/p$ where three Majorana masses $M_{fR}$ of $\nu_{fR}$ are of order $\Lambda$. (2) $\Sigma_f(p^2)=m_f^2/p$ where three Dirac masses $m_f=m_{(0)}1+m_{(3)}\lambda_3+m_{(8)}\lambda_8$ of SM fermions are {\it exponentially suppressed w.r.t. $\Lambda$}, and {\it degenerate for all SM fermions in $f$}. (1) $M_{fR}$ break $SU(3)_f$ symmetry completely; $m_{(3)},m_{(8)}$ superimpose the tiny breaking to $U(1) \times U(1)$. All flavor gluons thus acquire self-consistently the masses $\sim \Lambda$. (2) All $m_f$ break the electroweak $SU(2)_L \times U(1)_Y$ to $U(1)_{em}$. Symmetry partners of the composite Nambu-Goldstone bosons are the genuine Higgs particles: (1) Three $\nu_{R}$-composed Higgses $\chi_i$ with masses $\sim \Lambda$. (2) Two new SM-fermion-composed Higgses $h_3, h_8$ with masses $\sim m_{(3)}, m_{(8)}$, respectively. (3) The SM-like SM-fermion-composed Higgs $h$ with mass $\sim m_{(0)}$, the effective Fermi scale. $\Sigma_f(p^2)$-dependent vertices in the electroweak Ward-Takahashi identities imply: The axial-vector ones give rise to the $W$ and $Z$ masses at Fermi scale. The polar-vector ones give rise to the fermion mass splitting in $f$. At the present exploratory stage the splitting comes out unrealistic.

hep-ph↗

arXiv2020

Background for gravitational wave signal at LISA from refractive index of solar wind plasma

A strong indication is presented that the space-based gravitational antennas, in particular the LISA concept introduced in 2017 in response to the ESA call for L3 mission concepts, are going to be sensitive to a strong background signal interfering with the prospected signal of gravitational waves. The false signal is due to variations in the electron number density of the solar wind, causing variations in the refractive index of plasma flowing through interplanetary space. As countermeasures, two solutions are proposed. The first solution is to deploy enough solar wind detectors to the LISA mission to allow for reliable knowledge of the solar wind background. The second solution is to equip the LISA interferometer with a second laser beam with a distinct wavelength to allow cancelling of the background solar wind signal from the interferometric data.

astro-ph.IM↗

arXiv2019

Low-scale seesaw from neutrino condensation

Knowledge of the mechanism of neutrino mass generation would help understand a lot more about Lepton Number Violation (LNV), the cosmological evolution of the Universe, or the evolu tion of astronomical objects. Here we propose a verifiable and viable extension of the Standard model for neutrino mass generation, with a low-scale seesaw mechanism via LNV condensation in the sector of sterile neutrinos. To prove the concept, we analyze a simplified model of just one single family of elementary particles and check it against a set of phenomenological constraints coming from electroweak symmetry breaking, neutrino masses, leptogenesis and dark matter. The model predicts (i) TeV scale quasi-degenerate heavy sterile neutrinos, suitable for leptogenesis with resonant enhancement of the CP asymmetry, (ii) a set of additional heavy Higgs bosons whose existence can be challenged at the LHC, (iii) an additional light and sterile Higgs scalar which is a candidate for decaying warm dark matter, and (iv) a majoron. Since the model is based on simple and robust principles of dynamical mass generation, its parameters are very restricted, but remarkably it is still within current phenomenological limits.

hep-ph↗

arXiv2018

$0\nu\beta\beta$ nuclear matrix elements, neutrino potentials and $\mathrm{SU}(4)$ symmetry

Intimate relation between the Gamow-Teller part of the matrix element $M^{0\nu}_\mathrm{GT}$ and the $2\nu\beta\beta$ closure matrix element $M^{2\nu}_\mathrm{cl}$ is explained and explored. If the corresponding radial dependence $C^{2\nu}_\mathrm{cl}(r)$ would be known, $M^{0\nu}$ corresponding to any mechanism responsible for the $0\nu\beta\beta$ decay can be obtained as a simple integral. However, the $M^{2\nu}_\mathrm{cl}$ values sensitively depend on the properties of higher lying $1^+$ states in the intermediate odd-odd nuclei. We show that the $\beta^-$ and $\beta^+$ amplitudes of such states typically have opposite relative signs, and their contributions reduce severally the $M^{2\nu}_\mathrm{cl}$ values. Vanishing values of $M^{2\nu}_\mathrm{cl}$ are signs of a partial restoration of the spin-isospin $\mathrm{SU}(4)$ symmetry. We suggest that demanding that $M^{2\nu}_\mathrm{cl}$ = 0 is a sensible way, within the method of the Quasi-particle Random Phase Approximation (QRPA), of determining the amount of renormalization of isoscalar particle-particle interaction strength $g^{T=0}_{pp}$. Using such prescription, the matrix elements $M^{0\nu}$ are evaluated; their values are not very different ($\le$ 20\%) from the usual QRPA values when $g^{T=0}_{pp}$ is related to the known $2\nu\beta\beta$ half-lives.

nucl-th↗

arXiv2013

Electroweak symmetry breaking by dynamically generated masses of quarks and leptons

The aim of the thesis is to study models of the electroweak symmetry breaking caused by dynamically generated masses of quarks and leptons. (1) We perform the basic analysis whether the main underlying idea, that the masses of only known fermions can provide the electroweak symmetry breaking, is actually feasible. For that we elaborate a two-composite-Higgs-doublet model of the top-quark and neutrino condensation. The model suggests rather large number, $\mathcal{O}(100)$, of right-handed neutrinos. (2) We analyze the model of strong Yukawa dynamics where the dynamical fermion mass generation is provided by exchanges of new elementary massive complex doublet scalar fields. We focus on solving the coupled Schwinger--Dyson equations for fermion and scalar self-energies by means of approximative methods. We document that strongly hierarchical mass spectra can be reproduced. (3) We elaborate the flavor gauge model where the dynamical fermion mass generation is provided by asymptotically free non-Abelian self-breaking flavor gauge dynamics. We show that the Majorana type condensation of right-handed neutrinos in the flavor sextet representation triggers the complete flavor symmetry breaking. It leads to huge right-handed neutrino Majorana masses.

hep-ph↗

arXiv2013

Top-quark and neutrino composite Higgs bosons

In the context of top-quark condensation models, the top-quark alone is too light to saturate the correct value of the electroweak scale by its condensate. Within the seesaw scenario the neutrinos can have their Dirac masses large enough so that their condensates can provide significant contribution to the value of the electroweak scale. We address the question of a phenomenological feasibility of the top-quark and neutrino condensation conspiracy against the electroweak symmetry. Mandatory is to reproduce the masses of electroweak gauge bosons, the top-quark mass and the recently observed scalar mass of $125\,\mathrm{GeV}$ and to satisfy the upper limits on absolute value of active neutrino masses. To accomplish that we design a reasonably simplified effective model with two composite Higgs doublets. Additionally, we work with a general number $N$ of right-handed neutrino flavor triplets participating on the seesaw mechanism. There are no experimental constraints limiting this number. The upper limit is set by the model itself. Provided that the condensation scale is of order $10^{17-18}\,\mathrm{GeV}$ and the number of right-handed neutrinos is ${\cal O}(100-1000)$, the model predicts masses of additional Higgs bosons below $250\,\mathrm{GeV}$ and a suppression of the top-quark Yukawa coupling to the $125\,\mathrm{GeV}$ particle at the $\sim60\,%$ level of the Standard model value.

hep-ph↗

arXiv2011

Sterile Particles from the Flavor Gauge Model of Masses

The existence of right-handed neutrinos follows from theoretical consistence of the recently suggested electroweak symmetry breaking model, based on dynamical flavor gauge symmetry breaking. Only finite number of versions of the model exists. They differ by the number and the flavor structure of the right-handed neutrinos. We choose for inspection one of them, the non-minimal version with right-handed neutrinos in sextet flavor representation, and at some points we compare it with the minimal version. We show that a Majorana pairing of the sextet right-handed neutrinos is responsible for the flavor symmetry breaking, and the seesaw pattern of the neutrino mass matrix naturally arises. The dynamically generated neutrino mass matrix spontaneously breaks the lepton number and the chiral sterility symmetry of the right-handed neutrino sector. As a result spectrum of majorons, neutrino composites, manifests. We study main characteristics of both massive sterile neutrinos and majorons which show their relevance as dark matter candidates.

hep-ph↗

arXiv2011

Masses by gauge flavor dynamics

We gauge the experimentally observed flavor (family) index of chiral lepton and quark fields and argue that the resulting non-vectorial SU(3)_F dynamics completely self-breaks. This breakdown generates fermion masses, which in turn trigger electroweak symmetry breaking (EWSB). Suggested asymptotically free dynamics with an assumed non-perturbative infrared fixed point has just one free parameter and is therefore either right or plainly wrong. Weak point of field theories strongly coupled in the infrared, unfortunately, is that there is no reliable way of computing their spectrum. Because of its rigidity the model provides, however, rather firm theoretically safe experimental predictions without knowing the spectrum: First, anomaly freedom fixes the neutrino sector which contains almost sterile neutrino states. Second, global symmetries of the model, spontaneously broken by fermion masses imply the existence of a fixed pattern of (pseudo-)axions and (pseudo-)majorons. It is gratifying that the predicted both sterile neutrinos and the pseudo-Nambu--Goldstone bosons are the viable candidates for dark matter.

hep-ph↗

arXiv2009

Dynamical electroweak symmetry breaking due to strong Yukawa interactions

We present a new mechanism for electroweak symmetry breaking (EWSB) based on a strong Yukawa dynamics. We consider an SU(2)_L x U(1)_Y gauge invariant model endowed with the usual Standard model fermion multiplets and with two massive scalar doublets. We show that, unlike in the Standard model, EWSB is possible even with vanishing vacuum expectation values of the scalars. Such EWSB is achieved dynamically by means of the (presumably strong) Yukawa couplings and manifests itself by the emergence of fermion and gauge boson masses and scalar mass-splittings, which are expressed in a closed form in terms of the fermion and scalar proper self-energies. The `would-be' Nambu--Goldstone bosons are shown to be composites of both the fermions and the scalars. We demonstrate that the simplest version of the model is compatible with basic experimental constraints.

hep-ph↗