# Baryon Question

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#1
So I was given this question on a Kerboodle test:

Which of these hadrons could exist?
- ūud
- us
- ūd
- uus

I chose uus, but aparently the correct answer was ūd, the website said:
Incorrect. Hadrons are either baryons, made from three quarks (but not containing strange quarks), or mesons made from a quark–antiquark pair. The correct answer is ūd.

But isn't sigma a baryon with a strange quark? I looked up uus and it came up with Σ+: the sigma baryon. I'm really confused, is this test just incorrect or should I update my notes?
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#2
Anyone?
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2 years ago
#3
(Original post by Hughcifer)
So I was given this question on a Kerboodle test:

Which of these hadrons could exist?
- ūud
- us
- ūd
- uus

I chose uus, but aparently the correct answer was ūd, the website said:
Incorrect. Hadrons are either baryons, made from three quarks (but not containing strange quarks), or mesons made from a quark–antiquark pair. The correct answer is ūd.

But isn't sigma a baryon with a strange quark? I looked up uus and it came up with Σ+: the sigma baryon. I'm really confused, is this test just incorrect or should I update my notes?
Both uus and ūd are hadrons, since uus is a baryon with a single unit positive charge and ūd is a meson with -1charge, which both baryon and meson are hadrons . It’s probably only one answer is available per question.
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2 years ago
#4
I just recognise ūd as a pi minus meson.

The others dont make sense too me because they dont have integer charge.
ūud = -2/3 + 2/3 -1/3 = -1/3
us = 2/3 -1/3 = 1/3
ūd = -2/3 -1/3 = -1
uus = 2/3 + 2/3 -1/3 = 1

According to wikipedia "https://en.wikipedia.org/wiki/List_of_baryons" the uus baryon exists.
If you are willing to argue with the person or organisation who made the test feel free to do so.
The easy answer was ūd though, you should of memorised your quark combinations for pi mesons.
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#5
(Original post by Personinsertname)
I just recognise ūd as a pi minus meson.

The others dont make sense too me because they dont have integer charge.
ūud = -2/3 + 2/3 -1/3 = -1/3
us = 2/3 -1/3 = 1/3
ūd = -2/3 -1/3 = -1
uus = 2/3 + 2/3 -1/3 = 1

According to wikipedia "https://en.wikipedia.org/wiki/List_of_baryons" the uus baryon exists.
If you are willing to argue with the person or organisation who made the test feel free to do so.
The easy answer was ūd though, you should of memorised your quark combinations for pi mesons.
Ah, thanks for that. Kerboodle has always been a dodgy website anyway.
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