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Light flavor-singlet scalars and walking signals in Nf=8 QCD on the lattice

Yasumichi Aoki, Tatsumi Aoyama, Ed Bennett, Masafumi Kurachi, Toshihide Maskawa, Kohtaroh Miura, Kei-ichi Nagai, Hiroshi Ohki, Enrico Rinaldi, Akihiro Shibata, Koichi Yamawaki, Takeshi Yamazaki, Ed Bennett Orcid Logo

Physical Review D, Volume: 96, Issue: 1

Swansea University Author: Ed Bennett Orcid Logo

Abstract

Based on the highly improved staggered quark action, we perform lattice simulations of Nf=8 QCD and confirm our previous observation of a flavor-singlet scalar meson (denoted as σ) as light as the pion and various "walking signals" through low-lying spectra, with higher statistics, smaller...

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Published in: Physical Review D
ISSN: 2470-0010 2470-0029
Published: 2017
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URI: https://cronfa.swan.ac.uk/Record/cronfa34263
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We measure M&#x3C0;, F&#x3C0;, M&#x3C1;, Ma0, Ma1, Mb1, MN, M&#x3C3;, F&#x3C3;, &#x27E8;&#x3C8;&#xAF;&#x3C8;&#x27E9; (both directly and through the GMOR relation), and the string tension. The data are consistent with the spontaneously broken phase of the chiral symmetry, in agreement with the previous results: ratios of the quantities to M&#x3C0; monotonically increase in the smaller mf region towards the chiral limit similarly to Nf=4 QCD, in sharp contrast to Nf=12 QCD where the ratios become flattened. The hyperscaling relation holds with roughly a universal value of the anomalous dimension, &#x3B3;m&#x2243;1, with a notable exception of M&#x3C0; with &#x3B3;m&#x2243;0.6 as in the previous results. This is a salient feature ("walking signal") of Nf=8, unlike either Nf=4 which has no hyperscaling relation at all, or Nf=12 QCD which exhibits universal hyperscaling. We further confirm the previous observation of the light &#x3C3; with mass comparable to the pion in the studied mf region. In a chiral limit extrapolation of the &#x3C3; mass using the dilaton chiral perturbation theory and also using the simple linear fit, we find the value consistent with the 125 GeV Higgs boson within errors. Our results suggest that the theory could be a good candidate for walking technicolor model, having anomalous dimension &#x3B3;m&#x2243;1 and a light flavor-singlet scalar meson as a technidilaton, which can be identified with the 125 GeV composite Higgs in Nf=8 one-family model.</abstract><type>Journal Article</type><journal>Physical Review D</journal><volume>96</volume><journalNumber>1</journalNumber><publisher/><issnPrint>2470-0010</issnPrint><issnElectronic>2470-0029</issnElectronic><keywords>lattice gauge theory, walking technicolor, many-flavour QCD, beyond the standard model</keywords><publishedDay>18</publishedDay><publishedMonth>7</publishedMonth><publishedYear>2017</publishedYear><publishedDate>2017-07-18</publishedDate><doi>10.1103/PhysRevD.96.014508</doi><url/><notes/><college>COLLEGE NANME</college><department>Mathematics</department><CollegeCode>COLLEGE CODE</CollegeCode><DepartmentCode>SMA</DepartmentCode><institution>Swansea University</institution><apcterm/><lastEdited>2020-06-22T16:03:40.2796096</lastEdited><Created>2017-06-13T10:20:55.6224233</Created><path><level id="1">Faculty of Science and Engineering</level><level id="2">School of Biosciences, Geography and Physics - Physics</level></path><authors><author><firstname>Yasumichi</firstname><surname>Aoki</surname><order>1</order></author><author><firstname>Tatsumi</firstname><surname>Aoyama</surname><order>2</order></author><author><firstname>Ed</firstname><surname>Bennett</surname><order>3</order></author><author><firstname>Masafumi</firstname><surname>Kurachi</surname><order>4</order></author><author><firstname>Toshihide</firstname><surname>Maskawa</surname><order>5</order></author><author><firstname>Kohtaroh</firstname><surname>Miura</surname><order>6</order></author><author><firstname>Kei-ichi</firstname><surname>Nagai</surname><order>7</order></author><author><firstname>Hiroshi</firstname><surname>Ohki</surname><order>8</order></author><author><firstname>Enrico</firstname><surname>Rinaldi</surname><order>9</order></author><author><firstname>Akihiro</firstname><surname>Shibata</surname><order>10</order></author><author><firstname>Koichi</firstname><surname>Yamawaki</surname><order>11</order></author><author><firstname>Takeshi</firstname><surname>Yamazaki</surname><order>12</order></author><author><firstname>Ed</firstname><surname>Bennett</surname><orcid>0000-0002-1678-6701</orcid><order>13</order></author></authors><documents><document><filename>0034263-14062017133415.pdf</filename><originalFilename>nf8.pdf</originalFilename><uploaded>2017-06-14T13:34:15.5800000</uploaded><type>Output</type><contentLength>1041984</contentLength><contentType>application/pdf</contentType><version>Accepted Manuscript</version><cronfaStatus>true</cronfaStatus><embargoDate>2017-06-14T00:00:00.0000000</embargoDate><copyrightCorrect>true</copyrightCorrect><language>eng</language></document><document><filename>0034263-19072017081908.pdf</filename><originalFilename>PhysRevD.96.014508.pdf</originalFilename><uploaded>2017-07-19T08:19:08.4470000</uploaded><type>Output</type><contentLength>4194304</contentLength><contentType>application/pdf</contentType><version>Version of Record</version><cronfaStatus>true</cronfaStatus><embargoDate>2017-07-18T00:00:00.0000000</embargoDate><copyrightCorrect>true</copyrightCorrect><language>eng</language></document></documents><OutputDurs/></rfc1807>
spelling 2020-06-22T16:03:40.2796096 v2 34263 2017-06-13 Light flavor-singlet scalars and walking signals in Nf=8 QCD on the lattice e1a8e7927d2b093acdc54e74eac95e38 0000-0002-1678-6701 Ed Bennett Ed Bennett true false 2017-06-13 SMA Based on the highly improved staggered quark action, we perform lattice simulations of Nf=8 QCD and confirm our previous observation of a flavor-singlet scalar meson (denoted as σ) as light as the pion and various "walking signals" through low-lying spectra, with higher statistics, smaller fermion masses mf, and larger volumes. We measure Mπ, Fπ, Mρ, Ma0, Ma1, Mb1, MN, Mσ, Fσ, ⟨ψ¯ψ⟩ (both directly and through the GMOR relation), and the string tension. The data are consistent with the spontaneously broken phase of the chiral symmetry, in agreement with the previous results: ratios of the quantities to Mπ monotonically increase in the smaller mf region towards the chiral limit similarly to Nf=4 QCD, in sharp contrast to Nf=12 QCD where the ratios become flattened. The hyperscaling relation holds with roughly a universal value of the anomalous dimension, γm≃1, with a notable exception of Mπ with γm≃0.6 as in the previous results. This is a salient feature ("walking signal") of Nf=8, unlike either Nf=4 which has no hyperscaling relation at all, or Nf=12 QCD which exhibits universal hyperscaling. We further confirm the previous observation of the light σ with mass comparable to the pion in the studied mf region. In a chiral limit extrapolation of the σ mass using the dilaton chiral perturbation theory and also using the simple linear fit, we find the value consistent with the 125 GeV Higgs boson within errors. Our results suggest that the theory could be a good candidate for walking technicolor model, having anomalous dimension γm≃1 and a light flavor-singlet scalar meson as a technidilaton, which can be identified with the 125 GeV composite Higgs in Nf=8 one-family model. Journal Article Physical Review D 96 1 2470-0010 2470-0029 lattice gauge theory, walking technicolor, many-flavour QCD, beyond the standard model 18 7 2017 2017-07-18 10.1103/PhysRevD.96.014508 COLLEGE NANME Mathematics COLLEGE CODE SMA Swansea University 2020-06-22T16:03:40.2796096 2017-06-13T10:20:55.6224233 Faculty of Science and Engineering School of Biosciences, Geography and Physics - Physics Yasumichi Aoki 1 Tatsumi Aoyama 2 Ed Bennett 3 Masafumi Kurachi 4 Toshihide Maskawa 5 Kohtaroh Miura 6 Kei-ichi Nagai 7 Hiroshi Ohki 8 Enrico Rinaldi 9 Akihiro Shibata 10 Koichi Yamawaki 11 Takeshi Yamazaki 12 Ed Bennett 0000-0002-1678-6701 13 0034263-14062017133415.pdf nf8.pdf 2017-06-14T13:34:15.5800000 Output 1041984 application/pdf Accepted Manuscript true 2017-06-14T00:00:00.0000000 true eng 0034263-19072017081908.pdf PhysRevD.96.014508.pdf 2017-07-19T08:19:08.4470000 Output 4194304 application/pdf Version of Record true 2017-07-18T00:00:00.0000000 true eng
title Light flavor-singlet scalars and walking signals in Nf=8 QCD on the lattice
spellingShingle Light flavor-singlet scalars and walking signals in Nf=8 QCD on the lattice
Ed Bennett
title_short Light flavor-singlet scalars and walking signals in Nf=8 QCD on the lattice
title_full Light flavor-singlet scalars and walking signals in Nf=8 QCD on the lattice
title_fullStr Light flavor-singlet scalars and walking signals in Nf=8 QCD on the lattice
title_full_unstemmed Light flavor-singlet scalars and walking signals in Nf=8 QCD on the lattice
title_sort Light flavor-singlet scalars and walking signals in Nf=8 QCD on the lattice
author_id_str_mv e1a8e7927d2b093acdc54e74eac95e38
author_id_fullname_str_mv e1a8e7927d2b093acdc54e74eac95e38_***_Ed Bennett
author Ed Bennett
author2 Yasumichi Aoki
Tatsumi Aoyama
Ed Bennett
Masafumi Kurachi
Toshihide Maskawa
Kohtaroh Miura
Kei-ichi Nagai
Hiroshi Ohki
Enrico Rinaldi
Akihiro Shibata
Koichi Yamawaki
Takeshi Yamazaki
Ed Bennett
format Journal article
container_title Physical Review D
container_volume 96
container_issue 1
publishDate 2017
institution Swansea University
issn 2470-0010
2470-0029
doi_str_mv 10.1103/PhysRevD.96.014508
college_str Faculty of Science and Engineering
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hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Biosciences, Geography and Physics - Physics{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Biosciences, Geography and Physics - Physics
document_store_str 1
active_str 0
description Based on the highly improved staggered quark action, we perform lattice simulations of Nf=8 QCD and confirm our previous observation of a flavor-singlet scalar meson (denoted as σ) as light as the pion and various "walking signals" through low-lying spectra, with higher statistics, smaller fermion masses mf, and larger volumes. We measure Mπ, Fπ, Mρ, Ma0, Ma1, Mb1, MN, Mσ, Fσ, ⟨ψ¯ψ⟩ (both directly and through the GMOR relation), and the string tension. The data are consistent with the spontaneously broken phase of the chiral symmetry, in agreement with the previous results: ratios of the quantities to Mπ monotonically increase in the smaller mf region towards the chiral limit similarly to Nf=4 QCD, in sharp contrast to Nf=12 QCD where the ratios become flattened. The hyperscaling relation holds with roughly a universal value of the anomalous dimension, γm≃1, with a notable exception of Mπ with γm≃0.6 as in the previous results. This is a salient feature ("walking signal") of Nf=8, unlike either Nf=4 which has no hyperscaling relation at all, or Nf=12 QCD which exhibits universal hyperscaling. We further confirm the previous observation of the light σ with mass comparable to the pion in the studied mf region. In a chiral limit extrapolation of the σ mass using the dilaton chiral perturbation theory and also using the simple linear fit, we find the value consistent with the 125 GeV Higgs boson within errors. Our results suggest that the theory could be a good candidate for walking technicolor model, having anomalous dimension γm≃1 and a light flavor-singlet scalar meson as a technidilaton, which can be identified with the 125 GeV composite Higgs in Nf=8 one-family model.
published_date 2017-07-18T03:42:29Z
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score 11.035874