Higgs boson decay to fermions

[Silvestru]

Hello forum,

 

I was reading the below article about the Higgs boson decaying to fermions and I wanted to get your opinion.

 

https://home.cern/about/updates/2013/11/atlas-sees-higgs-boson-decay-fermions.

 

Is this article acurate? I know Photons and Gluons are out of the question but can other Bossons like Z or W decay into fermions too?

[swansont]

Hello forum,

 

I was reading the below article about the Higgs boson decaying to fermions and I wanted to get your opinion.

 

https://home.cern/about/updates/2013/11/atlas-sees-higgs-boson-decay-fermions.

 

Is this article acurate? I know Photons and Gluons are out of the question but can other Bossons like Z or W decay into fermions too?

As long as it's a fermion/anti-fermion pair, the fermion number remains zero and it's allowed.

[imatfaal]

As long as it's a fermion/anti-fermion pair, the fermion number remains zero and it's allowed.

 

Exactly - I believe the decay routes predicted and found towards fermions was to bottom quark / antiquark pair and to tau lepton/anti-lepton pair

 

For a Higgs boson mass of 125 GeV, the channels expected to be experimentally accessible include the decays to two photons, two W or Z bosons, a quark pair and a ττ lepton pair.

 

 

http://www.nature.com/nphys/journal/v10/n8/full/nphys3005.html

[Silvestru]

And do all particles decay at the same rate as their anti-particle equivalent.

 

I'm not trying to solve the baryon asymmetry here or anything but before your explanation I was under the impression that these bosons only create fermionic particles without the opposite equivalent.

 

There is nothing mentioned about anti particles in my posted link.

"Graphical representation of a Higgs boson decaying to two tau particles in the ATLAS detector. The taus decay into an electron (blue line) and a muon (red line)"

 

https://ibb.co/msHf3F

Edited June 9, 2017 by Silvestru

[Strange]

From the paper that imatfaal linked:

 

 

Therefore, the most promising experimental avenue to explore the direct coupling of the standard model Higgs boson to fermions is in the study of the decay to bottom quark–antiquark pairs (denoted as ) as well as to tau lepton–antilepton pairs (denoted as ττ).

[Sensei]

I'm not trying to solve the baryon asymmetry here or anything but before your explanation I was under the impression that these bosons only create fermionic particles without the opposite equivalent.

 

When there is created kaon, there must be created anti-kaon to conserve Strangeness.

The same is with the all other quantum numbers, Charmness, Topness, Bottomness.

 

Physicists are searching for violations of conservations of quantum numbers.

Edited June 9, 2017 by Sensei

[Strange]

 

 

And do all particles decay at the same rate as their anti-particle equivalent.

 

There can be variations, but I think they have only been observed for K and B mesons.

[Sensei]

 

There can be variations, but I think they have only been observed for K and B mesons.

 

Kaon indeed has two charge neutral variations, K⁰_L long and K⁰_S short, which have different half lives.

https://en.wikipedia.org/wiki/Kaon

Edited June 9, 2017 by Sensei

[imatfaal]

And do all particles decay at the same rate as their anti-particle equivalent.

 

I'm not trying to solve the baryon asymmetry here or anything but before your explanation I was under the impression that these bosons only create fermionic particles without the opposite equivalent.

 

There is nothing mentioned about anti particles in my posted link.

https://ibb.co/msHf3F

 

I think that is the nature of the press release that you were quoting - it is a very light weight treatment. The heavier documents start to mention the tau pairs and show that one is the anti-particle. The article I gave a link to is the document of record as a report of this experiment - ie it is the one without any dumbing down for non-scientists like me; this peer reviewed and highly detailed article is clear

 

Therefore, the most promising experimental avenue to explore the direct coupling of the standard model Higgs boson to fermions is in the study of the decay to bottom quark–antiquark pairs (denoted as ) as well as to tau lepton–antilepton pairs (denoted as ττ).

[Sensei]

(denoted as ττ)

 

 

Excuse me,

tau- anti-tau,

should be written as:

[math]\tau \bar{\tau}[/math]

 

(they lacked overline above anti-tau)

Edited June 10, 2017 by Sensei

[imatfaal]

 

 

Excuse me,

tau- anti-tau,

should be written as:

[math]\tau \bar{\tau}[/math]

 

(they lacked overline above anti-tau)

 

Yes - technically it should; I am unaware of why it isn't but I will note that in the said paper and in others talking of decay which I scoped on this topic pairs which are clearly described as lepton and anti-lepton are referred to in short as [math](\tau \tau)[/math] and even (ee) meaning an electron position pair. The paper was in Nature so it was hardly a lo-rent publication either. I am guessing it is a short-cut and tiny saving of time - but strikes me as sloppy

[swansont]

 

Yes - technically it should; I am unaware of why it isn't but I will note that in the said paper and in others talking of decay which I scoped on this topic pairs which are clearly described as lepton and anti-lepton are referred to in short as [math](\tau \tau)[/math] and even (ee) meaning an electron position pair. The paper was in Nature so it was hardly a lo-rent publication either. I am guessing it is a short-cut and tiny saving of time - but strikes me as sloppy

 

Publications meant for people in the field tend to be jargon-heavy. I'm guessing it's to keep from having to write "anti" a bunch of times. Pages cost money.

[imatfaal]

Publications meant for people in the field tend to be jargon-heavy. I'm guessing it's to keep from having to write "anti" a bunch of times. Pages cost money.

 

The bar over the "tau" or the "e" just seems lazy - but would you personally or any other atomic/nuclear/particle physicist read "the decay of a neutral boson to a tau pair" and think anything but a lepton / anti-lepton pair. Mainly cos the alternative would be the headline of the paper and nobel prize winning stuff if you could show such a breach of charge conservation.

 

I still wonder if has a greater meaning than an apparently lazy version of () which takes no more space etc. Wild thought - these particle/antiparticle pairs do not come into existence in potential states of superposition do they? That is to say: is highly technical shorthand for "one of or () or [latex]\frac{1}{\sqrt{2}}\left ( \tau_1 \bar{\tau_2} - \bar{\tau_1}\tau_2 \right )[/latex] etc. " or something else way way beyond my ken*

 

* the expression is meant to designate a pair of tau and anti-tau which must be heading in opposite directions and thus spatially separate but are existing in superposition as to which is tau and which is anti till measured and entanglement broken

[swansont]

 

The bar over the "tau" or the "e" just seems lazy - but would you personally or any other atomic/nuclear/particle physicist read "the decay of a neutral boson to a tau pair" and think anything but a lepton / anti-lepton pair. Mainly cos the alternative would be the headline of the paper and nobel prize winning stuff if you could show such a breach of charge conservation.

 

I still wonder if has a greater meaning than an apparently lazy version of () which takes no more space etc. Wild thought - these particle/antiparticle pairs do not come into existence in potential states of superposition do they? That is to say: is highly technical shorthand for "one of or () or [latex]\frac{1}{\sqrt{2}}\left ( \tau_1 \bar{\tau_2} - \bar{\tau_1}\tau_2 \right )[/latex] etc. " or something else way way beyond my ken*

 

* the expression is meant to designate a pair of tau and anti-tau which must be heading in opposite directions and thus spatially separate but are existing in superposition as to which is tau and which is anti till measured and entanglement broken

 

 

 

It could possibly be () or [latex]\frac{1}{\sqrt{2}}\left ( \tau_1 \bar{\tau_2} - \bar{\tau_1}\tau_2 \right )[/latex] (beyond what I've studied if this is a thing) but you have to have the antiparticle in there to conserve lepton number.

 

It occurs to me that saving space in a paper isn't the only pressure here, it also may be the economy how they speak (reminiscent of the Baryon Sweep terminology kerfuffle-that-shouldn't-have-been in a ST:TNG episode), and they are writing how they talk.

[imatfaal]

Do I lose all geek credentials because I had to look up ST:TNG on google? Just shows I was not cut out to be a scientist.

[Mordred]

Do I lose all geek credentials because I had to look up ST:TNG on google? Just shows I was not cut out to be a scientist.

Nah us geeks often have to look up new things. Otherwise we would get bored without new items to geek over.

[Sensei]

It occurs to me that saving space in a paper isn't the only pressure here, (...)

Just a few words prior [math]\tau\tau[/math] there was anti-bottom quark with proper overline..

 

quark-antiquark pairs (denoted as )

Looks to me as sloppy omission.

Edited June 11, 2017 by Sensei

[swansont]

Just a few words prior [math]\tau\tau[/math] there was anti-bottom quark with proper overline.. Looks to me as sloppy omission.

Did you read the rest of my comment?