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Related papers: Why the Four SM Families

200 papers

If the LHC experiments discover new particles that couple to the Standard Model fermions, then measurements by ATLAS and CMS can contribute to our understanding of the flavor puzzles. We demonstrate this statement by investigating a…

High Energy Physics - Phenomenology · Physics 2008-11-26 Yuval Grossman , Yosef Nir , Jesse Thaler , Tomer Volansky , Jure Zupan

We analyze the stability of the Higgs sector of a three-site model with flavor-non-universal gauge interactions, whose spectrum of non-Standard-Model states spans three orders of magnitude. This model is inspired by deconstructing a…

High Energy Physics - Phenomenology · Physics 2021-05-12 Lukas Allwicher , Gino Isidori , Anders Eller Thomsen

In the upcoming LHC Run 2, at $\sqrt{s} \sim13$ TeV, it is suggested to seek unusually charged ($Q= -4/3$ and $+5/3$) quarks with mass $M_Q \sim 3$ TeV which carry lepton number ($L = +2$ and $-2$ respectively) and decay superweakly to a…

High Energy Physics - Phenomenology · Physics 2015-04-23 Paul Howard Frampton

The Kobayashi-Maskawa (KM) hypothesis about the existence of a third generation of quarks represents a cornerstone of the Standard Model (SM). Fifty years after this seminal paper, flavor physics continues to represent a privileged…

High Energy Physics - Phenomenology · Physics 2023-08-23 Gino Isidori

The mass hierarchy among the three generations of quarks and charged leptons is one of the greatest mysteries in particle physics. In various flavor models, the origin of this phenomenon is attributed to a series of hierarchical spontaneous…

High Energy Physics - Phenomenology · Physics 2020-05-06 Admir Greljo , Toby Opferkuch , Ben A. Stefanek

In the Minimal Supersymmetric Standard Model (MSSM) with three generations of fermions, there is a stringent upper bound on the mass of the lightest neutral Higgs h, and the mass of the charged Higgs H^+, must be close (within tens of GeV)…

High Energy Physics - Phenomenology · Physics 2009-10-20 Sean Litsey , Marc Sher

The Littlest Higgs Model with T-parity (LHT) belongs to the simplest new physics scenarios with new sources of flavour and CP violation. We present a new analysis of quark observables in the LHT model in view of the oncoming flavour…

High Energy Physics - Phenomenology · Physics 2016-04-07 Monika Blanke , Andrzej J. Buras , Stefan Recksiegel

Flavour-Changing-Neutral-Currents (FCNC) play an important r\^ ole in testing the Standard Model (SM) while probing the possibility of having New Physics beyond the SM. In the SM, FCNC are forbidden at three level, but arise through…

High Energy Physics - Phenomenology · Physics 2013-08-22 G. C. Branco , M. N. Rebelo

We study some rare decays of $B_s$ meson governed by the quark level transitions $ b \to s$, in the fourth generation model popularly known as SM4. Recently it has been shown that SM4, which is a simple extension of the SM3, can…

High Energy Physics - Phenomenology · Physics 2013-05-30 R. Mohanta , A. K. Giri

In these proceedings, I present a composite Higgs model in which the flavour hierarchies between the third and light families emerge naturally. In particular, CKM mixing angles turn out to be suppressed while PMNS matrix remains anarchic.…

High Energy Physics - Phenomenology · Physics 2025-08-08 Javier M. Lizana

We argue that flavour mixing, both in the quark and charged lepton sector, is basically determined by the lightest family mass generation mechanism. So, in the chiral symmetry limit when the up and down quark masses vanish, all the quark…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. L. Chkareuli , C. D. Froggatt

A model describing the 4.1\sigma\ Wjj anomaly observed by the CDF experiment at the Tevatron collider is introduced. It features new scalar particles which are charged both under the SU(3)_C and the SU(2)_L gauge groups and which couple to…

High Energy Physics - Phenomenology · Physics 2015-06-03 Duccio Pappadopulo , Riccardo Torre

A simple breaking of the subnuclear democracy of the quarks leads to a mixing between the secons and the third family, in agreement with observation. Introducing the mixing between the first and the second family, one finds an interesting…

High Energy Physics - Phenomenology · Physics 2007-05-23 Harald Fritzsch

We explore Two Higgs Doublet Models with non-standard flavor structures. In analogy to the four, well studied, models with natural flavor conservation (type 1, type 2, lepton-specific, flipped), we identify four models that preserve an…

High Energy Physics - Phenomenology · Physics 2018-11-08 Wolfgang Altmannshofer , Brian Maddock

We ask what new states may lie at or below the TeV scale, with sizable flavour-dependent couplings to light quarks, putting them within reach of hadron colliders via resonant production, or in association with Standard Model states. In…

High Energy Physics - Phenomenology · Physics 2011-09-07 Gian Francesco Giudice , Ben Gripaios , Raman Sundrum

The nonbaryonic dark matter of the Universe can consist of new stable charged species, bound in heavy neutral "atoms" by ordinary Coulomb interaction. Stable $\bar U$ (anti-$U$)quarks of 4th generation, bound in stable colorless ($\bar U…

High Energy Physics - Phenomenology · Physics 2014-02-04 M. Yu. Khlopov , R. M. Shibaev

We investigate the experimentally allowed parameter space of an extension of the standard model (SM3) by one additional family of fermions. Therefore we extend our previous study of the CKM like mixing constraints of a fourth generation of…

High Energy Physics - Phenomenology · Physics 2010-12-13 Otto Eberhardt , Alexander Lenz , Jürgen Rohrwild

Flavor Democracy Hypothesis favors existence of iso-singlet quarks and vector-like charged leptons. Their observation at future colliders could shed light on the nature of mass and mixing patterns of known leptons and quarks, as well as…

High Energy Physics - Phenomenology · Physics 2021-03-16 Ali Osman Acar , Osman Emre Delialioglu , Saleh Sultansoy

Because of the top quark's very large mass, about 175~GeV, it now provides the best window into flavor physics. Thus, pair--production of top quarks at the Tevatron Collider is the best probe of this physics until the Large Hadron Collider…

High Energy Physics - Phenomenology · Physics 2016-09-01 Kenneth Lane

We address two fundamental aspects of flavor physics: the mass hierarchy and the large lepton mixing angles. On one side, left-right flavor symmetry realizes the democratic mass matrix patterns and explains why one family is much heavier…

High Energy Physics - Phenomenology · Physics 2008-11-26 Federica Bazzocchi , Stefano Morisi , Marco Picariello