All Questions
Tagged with beyond-the-standard-model higgs
69 questions
2
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Doublet-triplet splitting in GUT: how can the "color triplet" have mass?
I'm hopelessly perplexed about the $SU(5)$ doublet-triplet splitting.
I read that the color triplet part of the Higgs quintuplet needs to have extremely high mass compared to the "electroweak&...
- 53
3
votes
0
answers
88
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Is the Higgs VEV unnatural?
Is there some way to argue that the Higgs VEV is unnatural, without even bringing up the Higgs boson mass? For example, can one show that the Higgs vev receives large corrections from new physics? The ...
- 13.4k
2
votes
0
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42
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How did this generalized NJL model from 1993 predict Higgs boson and top quark masses?
Since the Higgs boson was found in 2012, at a mass around 125 GeV, it has often been remarked that this is curiously close to "criticality" or "metastability" or a false vacuum, if ...
- 13.4k
0
votes
1
answer
66
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Would observed limit on resonant double Higgs production the same if the scenario considered is spin $0$ scalar or spin $0$ radion particle?
At LHC, some analyses search for resonant HH production, from an unknown particle labelled $X$. They typically make the limit on cross-section of resonant HH production as a function of the spin of ...
1
vote
2
answers
149
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Number of free parameters in $SU(5)$ GUT model
Lately, I have been studying the potential of scalar fields in this theory. In general, what is the point of this GUT if, there, more free parameters have been added?
The standard Higgs potential in ...
- 357
2
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0
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180
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Yet another 'dimensional regularization vs. the Hierarchy Problem' one
My current point of view regarding the Hierarchy Problem is of agreement with Michael's answer in this question. Or, in the words of Manohar in his Introduction to EFT notes, using a cutoff regulator ...
- 1,782
1
vote
1
answer
105
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Do $Y$ bosons gain a little bit of mass from Higgs of $\bf 5$ rep in $SU(5)$ GUT theory?
I know that when the Higgs in the 24 rep takes a v.e.v. of this form $$v_{24}\,\mathrm{diag}\begin{pmatrix}
-\frac{2}{\sqrt{15}} & -\frac{2}{\sqrt{15}} & -\frac{2}{\sqrt{15}} & \frac{3}{\...
- 357
4
votes
2
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743
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Does $CP$-violation mean $CP$-odd?
This might be a very simple question but I'm doing some reading into the Higgs boson and $CP$-symmetry breaking. I've seen the terms $CP$-even and $CP$-odd terms in the Hamiltonian floated around and ...
- 43
0
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3
answers
584
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What are thought to be causes of the Mexican hat potential?
We all know the shape of the Mexican Hat Potential. It even serves as site logo.
It's a weird potential that has an actual existence in condensed state physics. It's for sure a possibility, and ...
2
votes
0
answers
130
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Tadpole VEV from a fermion loop?
We have one extra complex scalar $\Phi$ beyond the Standard Model (BSM) protected by an $U(1)$ global symmetry, which is broken by an Yukawa coupling $ y_\Phi \Phi \overline{\chi} \chi$, where $\chi$ ...
- 21
1
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0
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101
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Composite Higgs $SO(5)\to SO(4)$ model: how is $H$ a composite particle?
I am reading this review on CH models by Wulzer and Panico. In Section 2.2.2, they write a minimal model of $SO(5)$ breaking into $SO(4)$, triggering electroweak symmetry breaking (EWSB) with a ...
- 556
0
votes
1
answer
117
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What is the relation between custodial symmetry and $m_W = m_Z \cos \theta_W$?
In Wikipedia, we can read that custodial symmetry is responsible for keeping $m_W = m_Z \cos \theta_W$ in the SM. However, in 2HDM, the most general scalar potential doesn't have custodial symmetry (...
- 313
3
votes
1
answer
114
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Can the gauge boson respective of a spontaneously broken generator remain massless in the context of the Higgs Mechanism?
I'm studying a 3-3-1 model which is an extension of the standard model. The breaking $$SU(3)\times U(1) \to SU(2)\times U(1)'$$ occurs in a single step and through a single scalar VEV.
The problem is ...
- 1,782
4
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1
answer
656
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Is the discovery of the Higgs boson tantamount to discovering the Higgs mechanism?
Is the discovery of the Higgs boson tantamount to discovering the Higgs mechanism? I mean, it's clear by now that the Higgs boson is there, but what about the Higgs mechanism? How can we ever be sure ...
2
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2
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195
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Why is there a specific negative sign in front of the $m_{12}$ term of the 2HDM Higgs potential?
Why is there a specific negative sign in front of the $m_{12}$ term of the 2HDM Higgs potential?
(but not for the $m_{11}$ and $m_{22}$)
See for example: https://arxiv.org/abs/1106.0034
Eq. (2) Page 6:...
1
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0
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681
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What would a standard model that incorporates the SMASH particles look like?
I'm trying to create a standard model which incorporates the SMASH (Standard Model Axion Seesaw Higgs portal inflation) particles, but I'm having a hard time doing it because I'm unable to find as ...
- 136
1
vote
1
answer
54
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Dark standard model linked though Higgs
is it possible to have a dark std model (ie image of the std model) linked to the std model only through the Higgs? That would allow dark matter condensation, dark galaxies, stars, planets and biology....
- 65
0
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1
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97
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Higgs particles and Dark Matter particles
Usually, it is mentioned that the Higgs field IS the origin of mass for known fundamental particles.
If very heavy dark particles are found (heavier or much heavier than the top quark), should it mean ...
- 6,727
4
votes
1
answer
235
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How did Supersymmetry (incorrectly) predict the mass of the Higgs Boson?
In an article by CERN states
The minimal version of supersymmetry predicts that the Higgs boson mass should be less than 120-130 GeV
How was this conclusion reached? I could not find any answers on ...
- 41
2
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1
answer
300
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How SUSY solves the hierarchy problem?
I am struggling to understand the argument for why the introduction of a stop in SUSY can solve the hierarchy problem. The quadratic divergence from the top loop in the higgs mass calculation gives a ...
0
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1
answer
132
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What mechanism gives mass to elementary particles in string theory?
Nowadays it's assumed (it can still turn out to be different) that elementary particles are "given" mass by interaction with the Higgs field.
I read in the only answer to this question:
If you ...
2
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1
answer
565
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Why is the smallness of Higgs mass not technically natural?
Technical naturalness
The smallness of a parameter $\theta$ in the Lagrangian of a quantum field theory is said to be technically natural, if in the limit of vanishing $\theta$, the theory has some ...
- 27.2k
2
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1
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311
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How a discrete $Z_2$ symmetry removes flavour changing neutral current from Two Higgs Doublet Model?
By applying a discrete $Z_2$ symmetry to the theory of Two Higgs Doublet Model it is ensured that fermions of one type couples to only one doublet. But how FCNC is removed by doing so? Because if all ...
- 157
1
vote
1
answer
122
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2Higgs Doublet Models: Mechanism to set Yukawa Couplings to 0?
I just started having a look at 2 Higgs Doublet Models (2HDM) and came across this:
The general idea seems pretty simple. Introduce a second Higgs doublet that acquires a vev.
The general Yukawa ...
- 805
1
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0
answers
296
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Can someone explain Technicolor?
I read Wikipedia on Technicolor (and understood some of it - I am not a scientist)
Can someone give me a layman's definition?
Is the technicolor theory dead now that the Higgs has been found? Can ...
- 2,754
1
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0
answers
161
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Hierarchy problems: calculating the mass of the Higgs vs. other SM particles
While reading up on hierarchy problems in particle physics (wikipedia), I stumbled onto the statement that in the Standard Model, there is no hierarchy problem (or at least it cannot be formulated) ...
- 708
3
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1
answer
690
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Why do we need a two-Higgs doublet model and why only one extra doublet is added to the extension?
The general two higgs doublet model can neither give masses to neutrinos without considering a see-saw mechanism nor it can unify gravity with other three forces. To explain dark matter also we have ...
- 157
1
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0
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63
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Could electroweak interactions derive from higgsing of gauged chiral symmetry?
A recent question discussed the practice of introducing electroweak interactions into chiral perturbation theory by gauging part of the chiral symmetry. Gauging chiral symmetry is normally regarded as ...
- 13.4k
4
votes
1
answer
238
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Lepton flavor violating process on loop level $\mu \rightarrow e \gamma$ via Higgs, Divergent integral
I am stuck with calculating the proces $\mu \rightarrow e \gamma$ as in this diagram:
I wrote down the matrix element like this:
$$
\mathcal{M}=\bar{u}(p-q)\left[\int \frac{d^4k}{(2\pi)^4}A\frac{(k+...
- 153
1
vote
0
answers
127
views
Charge operator applied to matrix multiplets
In the context of SM ($SU(3)_C\otimes SU(2)_L\otimes U(1)_Y$) the charge operator is $Q_{SM} = T_3 + \frac{Y}{2}\mathbb{I}_2$ and gives us the fermions charges. Here $T_3=\frac{1}{2}\sigma_3$ is the ...
2
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1
answer
227
views
Does two Higgs doublet model predicts two Higgs bosons?
Does 2HDM predict two higgs boson? Why two doublets are needed? I need a simplified answer as i am new to BSM
2
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3
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3k
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Given the transformation of $SU(2)$ triplet $\vec{\phi}$ how to find the transformation of ${\Phi}\equiv\vec{\phi}\cdot\vec{\tau}$?
Given the transformation of a $SU(2)$ triplet $\vec\phi$ $$\phi\to \exp{(-i\vec{T}\cdot\vec{\theta})}~\vec\phi\tag{1}$$ (in the question here by @physicslover) how does obtain the transformation of $\...
- 27.2k
0
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1
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90
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Like the Higgs sector of the standard model, is there a SUSY sector which is also such a sector?
This question arose from an application of the virial theorem that showed how Bose-Einstein condensates of astrophysical dimension could arise from condensing clouds of normal phase bosons. If these ...
- 199
1
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2
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429
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Higgs doublet transformations
If we consider two complex Higgs doublets with $SU(3)_{c} \times SU(2)_L \times U(1)_Y$ quantum numbers $\phi_{A,B}$ ∼ (1,2,1), such that
$$\phi_A =
\begin{pmatrix}
\phi_{A}^{\dagger}\\
\dfrac{1}{\...
- 329
18
votes
3
answers
3k
views
What gives mass to dark matter particles?
Assuming that dark matter is not made of WIMPs (weakly interacting massive particles), but interacts only gravitationally, what would be the possible mechanism giving mass to dark matter particles? If ...
- 12.9k
0
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0
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58
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Would the existence of leptoquarks solve the hierarchy problem of the Higgs-boson?
Would the existence of leptoquarks solve the hierarchy problem of the Higgs-boson ? According to wikipedia these are assumed to be bosons which could contribute to the cancellation of the vacuum ...
- 10.2k
0
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1
answer
108
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What dictates the Higgs potential of the Standard model?
As far as I know, there is no convincing answer for why does the Higgs potential has a 'Mexican hat' shape. Apart from Lorentz invariance and gauge invariance, the Higgs potential of the Standard ...
- 27.2k
0
votes
1
answer
130
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Angular momentum conservation in the 2HDM
One of the experimentally searched decay chains of the 2HDM is the decay of a pseudoscalar Higgs boson A into the SM one and a Z boson. I was wondering how (from a very naive point of view) this works ...
- 11
6
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1
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531
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Why is the Standard model Higgs not a candidate of dark matter (in particular, a WIMP)?
Please consider me as a naive self-learner in this field.
The Standard Model (SM) Higgs boson is electrically neutral and has a mass of around $125$ GeV (which lies in the WIMP window i.e., between ...
- 27.2k
2
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0
answers
187
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How to gauge away Goldstone bosons in Higgs triplet model?
I'm studying the Higgs triplet model (HTM) in which you add a complex $SU(2)$ triplet (represented by a 2x2 matrix) to the standard model higgs sector. The thing is that I don't understand how to ...
2
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1
answer
324
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What is a holomorphic combination of standard model fields?
I am looking at exotic Higgs decay models like SM + Fermion and MSSM. In SM + Fermion the new fermion might have a three body decay and in MSSM for R-parity violating neutralino decays involve ...
- 822
4
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1
answer
235
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What is a Higgs Portal Scale?
I am reading about the prospective decay of Higgs into Majorana fermions (possibly sterile neutrinos). In the image the branching ratio of Higgs to a pair of Majorana fermions is given for different ...
- 822
0
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1
answer
362
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How to find vacuum expectation value of Higgs triplet?
I am trying to do a Higgs triplet extension of the standard model but I don't know how to find the corresponding vacuum expectation value for the Higgs triplet. I read a paper where they found the ...
- 385
-1
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1
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173
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Are the branching ratios of the Higgs boson decays consistent with the standard model? Is there only one type of Higgs boson? [closed]
Are the branching ratios of the Higgs boson decays consistent with the standard model?
Is there only one type of Higgs boson?
Why does it didn't have an electromagnetic field?
why it has no spin ?
...
user143869
21
votes
1
answer
3k
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What news about the second Higgs mode (or the mysterious particle) is anticipated to be seen at LHC around 750 GeV?
A few months ago, there were press releases about a possible second Higgs mode unveiled by LHC experiments. Or perhaps a new particle even more surprising like a graviton ... There was no certainty ...
- 10.8k
1
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0
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288
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How to represent su(2) Higgs triplet in 2x2 matrix form?
How to represent su(2) triplet(say Higgs triplet) in the 2x2 matrix form?
Please provide the mathematical reason behind it.
- 145
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1
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244
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If we were able to manipulate enough energy, could we use the higgs field for any practical application? [closed]
My question is, the fields in the standard model interact with each other, and when we are able to manipulate some of them through different engineered devices, we can transform the energy field into ...
user83548
6
votes
1
answer
1k
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2x2 Representation for triplet Higgs
I am perplexed by the $2\times2$ representation of the Higgs that one finds in Higgs triplet models and Left-Right symmetric models. If
$\vec{\phi}=(\phi^{++},\phi^{+},\phi^{0})\in(3,0)$ is the ...
0
votes
1
answer
122
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Why is $\sqrt{v_1+v_2+\ldots} =246$ GeV in multi-Higgs models?
Where does the condition come from that in models with several electroweak breaking doublets the square root of the squared sum of the VEVs should yield $246$ GeV?
- 10.3k
3
votes
1
answer
350
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Can a symmetry breaking VEV lie far above the "symmetry breaking scale?"
The scale where some symmetry gets broken can be computed using the renormalization group equations for the gauge couplings. If there is only one Higgs VEV responsible for some breaking, can this VEV ...
- 10.3k