Quark Content of these resonances

In summary, the charge and strangeness of a meson determines its quark content, regardless of its mass or resonance state.
  • #1
kuchenvater
9
0
Hi. I was reading an introductory book about particle physics and I visited the PDG for an exercise.
I found this...
http://pdg.lbl.gov/2014/tables/rpp2014-tab-mesons-strange.pdf
On page 9, the data of K1(1270) is given. How do I figure out it's quark content? If I look at the data for K*(892), it's easy to compare the data with the legend/key given right at the top of the pdf and figure out the quark content because the it mentions neutral and +/- resonances of K*(892) distinctly. But no such data is given for K1? Does it also have neutral and +/- varieties? Can I use some other property of this resonance to figure out its quark content? Am I missing something obvious here?
 
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  • #2
kuchenvater said:
Hi. I was reading an introductory book about particle physics and I visited the PDG for an exercise.
I found this...
http://pdg.lbl.gov/2014/tables/rpp2014-tab-mesons-strange.pdf
On page 9, the data of K1(1270) is given. How do I figure out it's quark content? If I look at the data for K*(892), it's easy to compare the data with the legend/key given right at the top of the pdf and figure out the quark content because the it mentions neutral and +/- resonances of K*(892) distinctly. But no such data is given for K1? Does it also have neutral and +/- varieties? Can I use some other property of this resonance to figure out its quark content? Am I missing something obvious here?
Why do you think resonances have different quark content?
 
  • #3
I thought since there are neutral and charged varieties of K*892, K1(1270) must have something similar going on... And as soon as their charges differ, their quark content would vary according to what's given in that box right at the top of the first page.
What is it's quark content then? There are multiple resonances in that data sheet with different I and JPC values. How do I figure out the quark content of each of those?
The s quark/antiquark is a given, how do I figure out whether the other quark is u or d?
Sorry, I'm a beginner in HEP.
 
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  • #4
kuchenvater said:
I thought since there are neutral and charged varieties of K*892, K1(1270) must have something similar going on... And as soon as their charges differ, their quark content would vary according to what's given in that box right at the top of the first page.
What is it's quark content then? There are multiple resonances in that data sheet with different I and JPC values. How do I figure out the quark content of each of those?
The s quark/antiquark is a given, how do I figure out whether the other quark is u or d?
Sorry, I'm a beginner in HEP.

All mesons (ordinary [itex]0^{ - }[/itex] and resonances [itex]1^{ - }[/itex]) have the same quark content [itex]q \bar{ q }[/itex], the so-called Meson Octets. For example [itex]K^{ 0 } \sim K^{ * 0 } = \bar{ s } d[/itex], [itex]K^{ + } \sim K^{ * + } = \bar{ s } u[/itex] and [itex]K^{ - } \sim K^{ * - } = \bar{ u } s[/itex]. You need to study the representation of the flavour group [itex]SU(3)[/itex]
 
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  • #5
What about K1 (1270) though? It's straightforward if you are dealing with a direct analogue like K0 and K*0.
What if it's K2 K2*, with completely different masses(1420 vs 1770)? Or K1 (1270) K1(1400)? Is their quark content identical despite the mass difference? If so why?
Maybe I'm having trouble phrasing this or maybe my knowledge isn't enough but I can't find anything about this in my books either.
 
  • #6
kuchenvater said:
What about K1 (1270) though? It's straightforward if you are dealing with a direct analogue like K0 and K*0.
What if it's K2 K2*, with completely different masses(1420 vs 1770)? Or K1 (1270) K1(1400)? Is their quark content identical despite the mass difference? If so why?
Maybe I'm having trouble phrasing this or maybe my knowledge isn't enough but I can't find anything about this in my books either.
Resonances are EXCITED STATES, they have different mass (energy) but the SAME structure. Does the ecited Hydrogen Atom has different structure (electronic content)?
 
  • #7
Ah. Right. Thanks. This is embarrassing.
So, K1 is an excited state of...K? K+/-? Or K0? Or K*?
 
  • #8
In case of the Delta baryon, it exists in four resonance states: two are excited analogues of the neutron and the proton and the other two are totally different. All four have different quark content. What I'm asking is in case of K1(1270) : is it an excited version of a certain kaon(and if so which one?) Is there a way to determine its quark content or wavefunction? Or are there differently charged varieties of K1(like there are of K*892) with all different quark contents?
http://pdg.lbl.gov/2014/tables/rpp2014-tab-mesons-strange.pdf
 
  • #9
kuchenvater said:
In case of the Delta baryon, it exists in four resonance states: two are excited analogues of the neutron and the proton and the other two are totally different. All four have different quark content. What I'm asking is in case of K1(1270) : is it an excited version of a certain kaon(and if so which one?) Is there a way to determine its quark content or wavefunction? Or are there differently charged varieties of K1(like there are of K*892) with all different quark contents?
http://pdg.lbl.gov/2014/tables/rpp2014-tab-mesons-strange.pdf

You are asking incorrect questions about subject you don’t understand yet. So, I would suggest that you get an elementary textbook about particle physics. Only then you will understand that resonances are excitations which appear in hadronic scattering processes and therefore differ only in orbital angular momentum.
As for the lowest [itex](3/2)^{ + }[/itex] baryons decuplet, it actually is ground state.
The quark content of any meson is determined by the charge and the strangeness of that meson. So, whether it is [itex]K_{1}[/itex] or [itex]K_{ x }[/itex] (whatever they might be), you need to know the charge and the strangeness of your meson.
 

Related to Quark Content of these resonances

What are quarks and why are they important in studying resonances?

Quarks are fundamental particles that make up protons and neutrons, which in turn make up the nucleus of an atom. They are important in studying resonances because the different types and combinations of quarks within a resonance can provide insight into its properties and behavior.

How do scientists determine the quark content of a resonance?

Scientists use a variety of methods, including particle accelerators and detectors, to study the interactions of particles in collisions. By analyzing the particles produced in these collisions, scientists can determine the types and combinations of quarks present in a resonance.

Can resonances have more than three quarks?

Yes, resonances can have more than three quarks. In fact, some resonances are made up of combinations of five or more quarks, known as pentaquarks. These types of resonances are still being studied and their properties are not yet fully understood.

Are certain types of quarks more common in resonances than others?

Yes, some types of quarks, such as up and down quarks, are more common in resonances. This is because these types of quarks have lower masses and are more stable, making them easier to produce in collisions.

How does the quark content of a resonance affect its decay?

The quark content of a resonance can greatly affect its decay behavior. For example, resonances with a combination of heavier quarks, such as charm or bottom quarks, are more likely to decay into other particles through the strong nuclear force. This can provide information about the strength of the strong nuclear force and the properties of the resonance itself.

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