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Alfredo Aranda

Publications and source records attributed to Alfredo Aranda.

At least 19 recordsLinked to original sources

Production of Magic States via $Z$ Bosons and Dark Photons

The production of magic states is studied in two settings. The first is the electroweak (EW) sector of the Standard Model (SM). The second is an extension featuring a new broken $U(1)$ gauge symmetry and a Dirac fermion charged under it. This setup resembles a dark $U(1)$ scenario, with the additional fermion playing the role of a dark matter candidate that annihilates into SM particles through its coupling to the new gauge boson. In the EW sector, the low-energy regime reproduces earlier magic production results obtained for Quantum Electrodynamics, whereas the high-energy and $Z$-resonance regimes generate new magic distribution functions and non-trivially reorganize the stabilizer state classes, with Bhabha scattering exhibiting the strongest sensitivity to electroweak effects. Also, a subset of fixed stabilizer states is identified, for which the magic distributions remain unchanged across the different energy regimes. In the dark sector, the main effect of the new massive mediator is the appearance of new magic distributions functions for Moller-like, Bhabha-like, and inverse pair-annihilation processes in the low-energy limit. These reach the maximal magic value at the SM-to-dark fermion mass ratios $m_f/m_\chi \to 0$ and $m_f/m_\chi\to 1.83929$.

hep-ph

Rolling Down the Leptonic BSM Landscape Using Machine Learning Techniques

In this work, we adapt and apply techniques from machine learning to the exploration of physics beyond the Standard Model in the leptonic sector. Namely, we employ initialization and optimization, as they are applied in machine learning, to minimize a loss function that describes textures or conditions which we want in the neutrino mass matrix. The model free parameters are explored during the optimization, and after training for a number of optimization steps, we obtain matrices that approximately follow the desired forms, as well as their corresponding optimized parameters. We also discuss extensions and additional applications of the ideas presented here in conjunction with other methods based on artificial intelligence.

hep-ph

Charged Higgs Decay to Bottom and Charm Quarks from $Z_3$-Flavored Two Higgs Doublet Models

The phenomenology of a charged Higgs present in a model with two Higgs SU(2) doublets and a $Z_3$ flavor symmetry is analyzed. It is shown that it is possible to generate an enhancement of its flavor changing coupling to c and b quarks and also to reproduce the ATLAS excess associated to the process $H^\pm \to bc$ for a charge Higgs mass of $130$~GeV. Furthermore, by considering the possibility of a search at the future LHeC, the analysis suggests viability for its detection.

hep-ph

Multi-component Dark Matter from an $SU(2)_{D}\to Z_{3}^{D}\times Z_{2}^{\text{acc}}$ scenario

A multi-component weakly-interacting dark matter scenario is analyzed, where the candidate dark matter states arise from the $SU(2)_{D}\to Z_{3}^{D}\times Z_{2}^{\text{acc}}$ symmetry breaking triggered by a VEV-developing scalar in the $J=3/2$ representation. While the discrete symmetries guarantee at least two stable states, a closer look at the mass orderings of the contrived dark sector reveals the existence of a third dark matter candidate, whose stability effectively results from the tight phase space in the dark boson sector. Regions of masses and couplings where the three dark states furnish a comparable contribution to the observed relic abundance are determined numerically.

hep-ph

Can $E_8$ unification at low energies be consistent with proton decay?

A model is presented that achieves unification of the full Standard Model (SM) field content into a single superfield. It has $E_8$ as a gauge group and simple SUSY in ten spacetime dimensions. The extra dimensions are orbifolded such that they reduce the gauge symmetry directly to the SM one. At low energies, only the SM field content remains with viable unified Yukawa couplings. Full unification can be achieved at energies as low as $10^6\ \rm{GeV}$ with controlled proton decay.

hep-ph

New insights on the quantum-classical division in light of Collapse Models

We argue, in light of Collapse Model interpretation of quantum theory, that the fundamental division between the quantum and classical behaviors is analogous to the division of thermodynamic phases. A specific relationship between the collapse parameter $(λ)$ and the collapse length scale ($r_C$) plays the role of the coexistence curve in usual thermodynamic phase diagrams. We further claim that our functional relationship between $λ$ and $r_C$ is strongly supported by the existing IGEX collaboration data. This result is preceded by a self-contained discussion of quantum measurement theory and the Ghirardi-Rimini-Weber (GRW) model applied to the free wavepacket dynamics.

quant-ph

Sculpting the Standard Model from low-scale Gauge-Higgs-Matter $E_8$ Grand Unification in ten dimensions

The construction and general implications of a model with complete supersymmetric unification of the Standard Model matter content, interactions and families' replication into a single $E_{8}$ gauge superfield in ten dimensions is presented. The gauge and extended Poincaré symmetries are broken through compactification of the $\mathbb{T}^6/(\mathbb{Z}_3\times \mathbb{Z}_3)$ orbifold with Wilson lines, which reduces the original symmetry and matter content into those of the Standard Model plus additional heavier states. Proton decay can be suppressed automatically while the compactification scale may be as low as $10^9~\rm{GeV}$, so that the corresponding GUT-scale physics may be potentially accessible and testable by future collider measurements.

hep-ph

Sub-GeV $U(1)_{R}$ gauge boson to address the proton radius discrepancy

We propose a Standard Model extension by a $U(1)_{R}$ gauge symmetry where only right-handed chiral fermions can carry a non-trivial charge. Here we show that the simplest anomaly-free solution to accommodate the proton charge radius discrepancy takes right-handed muons $μ_R$ and first generation quarks, $u_R$ and $d_R$. Consistency with the latest muon's $(g-2)$ measurements is achieved through an extra light scalar, which itself must lie in the tens of MeV mass range to be viable.

hep-ph

Complete $E_8$ Unification in 10 Dimensions

A grand unification model with a single $E_8$ gauge superfield in 10 dimensions is presented. It is shown that, through the orbifold $T^6/(\mathbb{Z}_6\times \mathbb{Z}_2)$ and its corresponding Wilson lines, the symmetry is broken to the Standard Model one. Furthermore it is shown that the model is anomaly free at all levels without the need to add any extra field content. Thus a complete unification of the Standard Model into a single gauge superfield is achieved consistently.

hep-ph

Gauge couplings evolution from the Standard Model, through Pati-Salam theory, into $E_8$ unification of families and forces

We explore the potential of ultimate unification of the Standard Model matter and gauge sectors into a single $E_8$ superfield in ten dimensions via an intermediate Pati-Salam gauge theory. Through a consistent realisation of a $\mathbb{T}^6/(\mathbb{Z}_6\times \mathbb{Z}_2)$ orbifolding procedure accompanied by the Wilson line breaking mechanism and Renormalisation Group evolution of gauge couplings, we have established several benchmark scenarios for New Physics that are worth further phenomenological exploration.

hep-ph

Exceptional Unification of Families and Forces

This work considers the remarkable suggestion that the three families of quarks and leptons may be unified, together with the Higgs and gauge fields of the Standard Model (SM), into a single "particle", namely the $\textbf{248}$ vector superfield of a ten-dimensional $E_8$ super Yang Mills (SYM) theory. Towards a realistic model along these lines, a class of orbifoldings based on $T^6/(\mathbb{Z}_N\times \mathbb{Z}_M)$ are proposed and explored, that can in principle break $E_8$ SYM down to the minimal supersymmetric standard model (MSSM), embedded in a larger group such as $E_6$, $SO(10)$ or $SU(5)$, together with other gauge group factors which can be broken by Wilson lines. A realistic model based on $T^6/(\mathbb{Z}_6\times \mathbb{Z}_2)$ is presented. The orbifold breaks $E_8$ SYM down to a Pati-Salam gauge group in 4d, together with other gauge groups, which are further broken to the SM by Wilson lines in the right-handed sneutrino directions, yielding proto-realistic fermion mass matrices, and experimental signals associated with a low Pati-Salam gauge group breaking scale.

hep-ph

Gauge-flavon unification

In this paper we propose the idea that flavons can emerge from extra dimensional gauge fields, referred to as gauge-flavon unification (GFU) analogous to gauge-Higgs unification (GHU). We assume that there is a gauged family symmetry in extra dimensions and that the flavons are the extra dimensional components of the gauge field. This provides a simple mechanism to align the VEVs of the flavons through a combination of Wilson lines and orbifold symmetry breaking. We present some simple 5d examples of GFU based on $SO(3)$ and $SU(4)$ gauged family symmetry, the latter case yielding $SU(3)\times U(1)$ gauged family symmetry in 4d, broken by triplet and antitriplet flavons, with effective couplings to fermions. We also present a general formalism for Wilson lines and orbifolds, in any number of dimensions, including non-commutative aspects Wilson lines, which may be useful for aligning additional flavons as required for realistic models.

hep-ph

Dynamical generation of neutrino mass scales

In this letter we present a simple scenario where the mass scales associated to atmospheric and solar neutrino oscillations are obtained through the dynamical generation of neutrino masses. The main idea is that the two different scales are the result of two independent mechanisms, namely a type-I seesaw generating the atmospheric scale and a radiative 1-loop process providing the solar one. A relation of the two scales, reminiscent of the so-called sequential dominance, is thus obtained.

hep-ph

Standard Model Extension with Flipped Generations

An extension of the Standard Model is presented that leads to the possible existence of new gauge bosons with masses in the range of a few TeV. Due to the fact that their couplings to Standard Model fermions are strongly suppressed, it is possible for them to be hidden from current searches. The model contains additional generations of fermions with quantum numbers resembling those of the Standard Model fermion generations but with a twist: their charge assignments are such that their electric charges and chiralities are flipped with respect to those of their corresponding Standard Model counterparts. This feature provides a way to obtain potential dark matter candidates and the interesting possibility for a Lepton number conserving dimension-five operator for Dirac neutrino masses. The model implications associated to electroweak precision parameters, flavor changing neutral currents, and diphoton rate contributions are briefly discussed. The general assumptions of this set up are also used to sketch a couple of variants of the model with peculiar features that could motivate further study.

hep-ph

When the C in CP does not matter: anatomy of order-4 CP eigenstates and their Yukawa interactions

We explore the origin and Yukawa interactions of the scalars with peculiar CP-properties which were recently found in a multi-Higgs model based on an order-4 CP symmetry. We relate the existence of such scalars to the enhanced freedom of defining CP, even beyond the well-known generalized CP symmetries, which arises in models with several zero-charge scalar fields. We also show that despite possessing exotic CP quantum numbers, these scalars do not have to be inert: they can have CP-conserving Yukawa interactions provided the CP acts on fermions by also mixing generations. This paper focuses on formal aspects---exposed in a pedagogical manner---and includes a brief discussion of possible phenomenological consequences.

hep-ph

A new radiative neutrino mass generation mechanism with higher dimensional scalar representations and custodial symmetry

A new realization for radiative neutrino mass generation is presented. Based on the requirement of tree-level custodial symmetry and the introduction of higher (greater than two) dimensional representations for scalar fields, a specific scenario with a scalar septet is presented that generates neutrino Majorana masses radiatively. This is accomplished through an eleven dimensional operator that requires the addition of several scalar fields and a SU(2) 5-plet of new fermions, together with a Z2 that guarantees the preservation of custodial symmetry. The phenomenology of the setup is rather rich and includes a dark matter candidate

hep-ph

Magnetic dipole moments for composite dark matter

We study neutral dark matter candidates with a nonzero magnetic dipole moment. We assume that they are composite states of new fermions related to the strong phase of a new gauge interaction. In particular, invoking a dark flavor symmetry, we analyze the composition structure of viable candidates depending on the assignations of hypercharge and the multiplets associated to the fundamental constituents of the extended sector. We determine the magnetic dipole moments for the neutral composite states in terms of their constituents masses.

hep-ph

Electroweak phase transition in a model with gauged lepton number

In this work we study the electroweak phase transition in a model with gauged lepton number. Here, a family of vector-like leptons is required in order to cancel the gauge anomalies. Furthermore, these leptons can play an important role in the transition process. We find that this framework is able to provide a strong transition, but only for a very limited number of cases.

hep-ph