5 ms·

Why does nobody include the particle name in the heading? Supersymmetry?!? Click. Nope, some pseudo particle or a bunch of quarks.

by danbruc 12y ago

AnimalMuppet 12y ago
I'll go a bit further. Even the article body didn't say much. They're bosons? Great. A bit more detail? Masses? Names? Anything? Nope.
- tjradcliffe 12y ago
  According to the preprint linked above they are hybrid equivalents of the proton or neutron. Protons and neutrons are made of up and down quarks. Protons are uud, neutrons are ddu. (d have charge -1/3, u +2/3, so neutrons have no net charge, protons +1). There are three "generations" of quarks, each one heavier than the last but otherwise identical in properties. These are charm and strange followed by top and bottom. These new particles are a mix of generations: bds (bottom, down, strange). They are predicted by the Standard Model, but their detailed properties (particularly their branching ratios to various decays into other particles) will be slightly different in theories of "physics beyond the Standard Model", so by looking at them in detail, including a precision measurement of their masses, it may be possible to kill off some alternative theories.
  - danbruc 12y ago
    The comment wasn't to serious but it just happened a couple of times recently that I spotted similar headings and after excitingly clicking on them expecting or at least hoping for a major breakthrough like a superpartner or magnetic monopoles it turns out to be a tetraquark, a quasi monopole or now a Xi. Not that these are not interesting or that a single click matters.
pbhjpbhj 12y ago
"0b" [that's a copy paste, the Xi doesn't appear, the super and subscript letters do, the pi doesn't show] I'm going to guess that is why? Though the OP does say "The discovery of the particles, known as Xi_b'- and Xi_b*-, were announced by CERN [...]" 𝛯′⁻ works in unicode, but I can't get the subscript b nor superscript asterisk in there (cf. http://en.wikipedia.org/wiki/Unicode_subscripts_and_superscripts http://en.wikipedia.org/wiki/Unicode_subscripts_and_superscr...).
- deleted 12y ago
  [deleted]
- sp332 12y ago
  I don't see a subscript-b in Unicode anywhere.
  - pbhjpbhj 12y ago
    No, me neither, nor a superscript asterisk.
cozzyd 12y ago
Because \Xi'_b and \Xi*_b don't mean anything to most people. Even "excited baryon states" is pushing it.
jontas 12y ago
From one of the articles linked in in the HN comments [0]: > The particles, known as the Xi_b'- and Xi_b-, were predicted to exist by the quark model but had never been seen before. A related particle, the Xi_b0, was found by the CMS experiment at CERN in 2012. The LHCb collaboration submitted a paper reporting the finding to Physical Review Letters.* 0: http://home.web.cern.ch/about/updates/2014/11/lhcb-observes-two-new-baryon-particles http://home.web.cern.ch/about/updates/2014/11/lhcb-observes-... * some of the formatting of the particle names got borked by the HN comment system limitations--I tried using <sup> tags but they don't appear to work. The correct spelling/representation of the particle names can be found in [0]

Why does nobody include the particle name in the heading? Supersymmetry?!? Click. Nope, some pseudo particle or a bunch of quarks.

by danbruc 12y ago

Why does nobody include the particle name in the heading? Supersymmetry?!? Click. Nope, some pseudo particle or a bunch of quarks.

AnimalMuppet 12y ago

I'll go a bit further. Even the article body didn't say much. They're bosons? Great. A bit more detail? Masses? Names? Anything? Nope.

tjradcliffe 12y ago
According to the preprint linked above they are hybrid equivalents of the proton or neutron. Protons and neutrons are made of up and down quarks. Protons are uud, neutrons are ddu. (d have charge -1/3, u +2/3, so neutrons have no net charge, protons +1). There are three "generations" of quarks, each one heavier than the last but otherwise identical in properties. These are charm and strange followed by top and bottom. These new particles are a mix of generations: bds (bottom, down, strange). They are predicted by the Standard Model, but their detailed properties (particularly their branching ratios to various decays into other particles) will be slightly different in theories of "physics beyond the Standard Model", so by looking at them in detail, including a precision measurement of their masses, it may be possible to kill off some alternative theories.
- danbruc 12y ago
  The comment wasn't to serious but it just happened a couple of times recently that I spotted similar headings and after excitingly clicking on them expecting or at least hoping for a major breakthrough like a superpartner or magnetic monopoles it turns out to be a tetraquark, a quasi monopole or now a Xi. Not that these are not interesting or that a single click matters.

pbhjpbhj 12y ago

"0b" [that's a copy paste, the Xi doesn't appear, the super and subscript letters do, the pi doesn't show] I'm going to guess that is why? Though the OP does say "The discovery of the particles, known as Xi_b'- and Xi_b*-, were announced by CERN [...]" 𝛯′⁻ works in unicode, but I can't get the subscript b nor superscript asterisk in there (cf. http://en.wikipedia.org/wiki/Unicode_subscripts_and_superscripts http://en.wikipedia.org/wiki/Unicode_subscripts_and_superscr...).

deleted 12y ago
[deleted]
sp332 12y ago
I don't see a subscript-b in Unicode anywhere.
- pbhjpbhj 12y ago
  No, me neither, nor a superscript asterisk.

cozzyd 12y ago

Because \Xi'_b and \Xi*_b don't mean anything to most people. Even "excited baryon states" is pushing it.

jontas 12y ago

From one of the articles linked in in the HN comments [0]: > The particles, known as the Xi_b'- and Xi_b-, were predicted to exist by the quark model but had never been seen before. A related particle, the Xi_b0, was found by the CMS experiment at CERN in 2012. The LHCb collaboration submitted a paper reporting the finding to Physical Review Letters.* 0: http://home.web.cern.ch/about/updates/2014/11/lhcb-observes-two-new-baryon-particles http://home.web.cern.ch/about/updates/2014/11/lhcb-observes-... * some of the formatting of the particle names got borked by the HN comment system limitations--I tried using <sup> tags but they don't appear to work. The correct spelling/representation of the particle names can be found in [0]