Unconventional Mechanisms of Heavy Quark Fragmentation
Heavy and light quarks produced in high-<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>p</mi><mi>T</mi></msub></semantics></math></inline-formula> parto...
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MDPI AG
2023-09-01
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| Series: | Universe |
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| Online Access: | https://www.mdpi.com/2218-1997/9/9/418 |
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| author | Boris Kopeliovich Jan Nemchik Irina Potashnikova Ivan Schmidt |
| author_facet | Boris Kopeliovich Jan Nemchik Irina Potashnikova Ivan Schmidt |
| author_sort | Boris Kopeliovich |
| collection | DOAJ |
| description | Heavy and light quarks produced in high-<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>p</mi><mi>T</mi></msub></semantics></math></inline-formula> partonic collisions radiate differently. Heavy quarks regenerate their color field, stripped-off in the hard reaction, much faster than the light ones and radiate a significantly smaller fraction of the initial quark energy. This peculiar feature of heavy-quark jets leads to a specific shape of the fragmentation functions observed in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup></mrow></semantics></math></inline-formula> annihilation. Differently from light flavors, the heavy quark fragmentation function strongly peaks at large fractional momentum <i>z</i>, i.e., the produced heavy–light mesons, <i>B</i> or <i>D</i>, carry the main fraction of the jet momentum. This is a clear evidence of the dead-cone effect, and of a short production time of a heavy–light mesons. Contrary to propagation of a small <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>q</mi><mover accent="true"><mi>q</mi><mo>¯</mo></mover></mrow></semantics></math></inline-formula> dipole, which survives in the medium due to color transparency, a heavy–light <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>Q</mi><mover accent="true"><mi>q</mi><mo>¯</mo></mover></mrow></semantics></math></inline-formula> dipole promptly expands to a large size. Such a big dipole has no chance to remain intact in a dense medium produced in relativistic heavy ion collisions. On the other hand, a breakup of such a dipole does not affect much the production rate of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>Q</mi><mover accent="true"><mi>q</mi><mo>¯</mo></mover></mrow></semantics></math></inline-formula> mesons, differently from the case of light <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>q</mi><mover accent="true"><mi>q</mi><mo>¯</mo></mover></mrow></semantics></math></inline-formula> meson production. |
| first_indexed | 2024-03-10T21:53:39Z |
| format | Article |
| id | doaj.art-6eb8ca556b5f47a197c3317aa2331e9d |
| institution | Directory Open Access Journal |
| issn | 2218-1997 |
| language | English |
| last_indexed | 2024-03-10T21:53:39Z |
| publishDate | 2023-09-01 |
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| record_format | Article |
| series | Universe |
| spelling | doaj.art-6eb8ca556b5f47a197c3317aa2331e9d2023-11-19T13:17:43ZengMDPI AGUniverse2218-19972023-09-019941810.3390/universe9090418Unconventional Mechanisms of Heavy Quark FragmentationBoris Kopeliovich0Jan Nemchik1Irina Potashnikova2Ivan Schmidt3Departamento de Física, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390123, ChileFaculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Břehová 7, 11519 Prague, Czech RepublicDepartamento de Física, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390123, ChileDepartamento de Física, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390123, ChileHeavy and light quarks produced in high-<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>p</mi><mi>T</mi></msub></semantics></math></inline-formula> partonic collisions radiate differently. Heavy quarks regenerate their color field, stripped-off in the hard reaction, much faster than the light ones and radiate a significantly smaller fraction of the initial quark energy. This peculiar feature of heavy-quark jets leads to a specific shape of the fragmentation functions observed in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup></mrow></semantics></math></inline-formula> annihilation. Differently from light flavors, the heavy quark fragmentation function strongly peaks at large fractional momentum <i>z</i>, i.e., the produced heavy–light mesons, <i>B</i> or <i>D</i>, carry the main fraction of the jet momentum. This is a clear evidence of the dead-cone effect, and of a short production time of a heavy–light mesons. Contrary to propagation of a small <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>q</mi><mover accent="true"><mi>q</mi><mo>¯</mo></mover></mrow></semantics></math></inline-formula> dipole, which survives in the medium due to color transparency, a heavy–light <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>Q</mi><mover accent="true"><mi>q</mi><mo>¯</mo></mover></mrow></semantics></math></inline-formula> dipole promptly expands to a large size. Such a big dipole has no chance to remain intact in a dense medium produced in relativistic heavy ion collisions. On the other hand, a breakup of such a dipole does not affect much the production rate of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>Q</mi><mover accent="true"><mi>q</mi><mo>¯</mo></mover></mrow></semantics></math></inline-formula> mesons, differently from the case of light <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>q</mi><mover accent="true"><mi>q</mi><mo>¯</mo></mover></mrow></semantics></math></inline-formula> meson production.https://www.mdpi.com/2218-1997/9/9/418quarksjetsfragmentationhadronization |
| spellingShingle | Boris Kopeliovich Jan Nemchik Irina Potashnikova Ivan Schmidt Unconventional Mechanisms of Heavy Quark Fragmentation Universe quarks jets fragmentation hadronization |
| title | Unconventional Mechanisms of Heavy Quark Fragmentation |
| title_full | Unconventional Mechanisms of Heavy Quark Fragmentation |
| title_fullStr | Unconventional Mechanisms of Heavy Quark Fragmentation |
| title_full_unstemmed | Unconventional Mechanisms of Heavy Quark Fragmentation |
| title_short | Unconventional Mechanisms of Heavy Quark Fragmentation |
| title_sort | unconventional mechanisms of heavy quark fragmentation |
| topic | quarks jets fragmentation hadronization |
| url | https://www.mdpi.com/2218-1997/9/9/418 |
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