Kazem Azizi Doğuş University

10-15 June 2019

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Recent Theoretical and Experimental Progresses in Hadron Physics

3rd International Turkey-Iran Joint Conference on LHC Physics

v  Standard & non-conventional hadrons: some progresses v  New physics effects: LFUV

v  S-Hexaquark (uuddss): a candidate for dark matter? v  Concluding remarks

... Will be discussed

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v  Standard & non-conventional hadrons: recent progresses

Mesons: one quark+ one anti-quark

Baryons: 3 quarks Standard hadrons

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Exotic or non-conventional states:

Tetraquarks, Meson Molecules Pentaquarks, Meson-Baryon Molecules Hybrids (baryon, meson) Glueballs Di-baryons, Hexaquarks ….....

Situation in the Experiment 1- All light baryons predicted by the quark model and many of their resonances have been discovered. Belle discovered a new state Ω (2012) (23 May 2018). 2- The PS and vector nonets of light mesons and some of their excited states have been observed. There are some problems with the light scalar and axial vector mesons. The mass and width of scalar mesons suffer from large uncertainties. For example, for f0(500): see PDG 13/06/19 4

Standard hadrons

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3-All single-charmed baryons and some of their resonances have been observed. Recently five narrow Ωc resonances have been discovered by LHCb. But the LHCb could not fix their exact quantum numbers and internal quark organizations. Theoretical and experimental studies are continued in this regard. 4- The single charmed PS and Vector mesons have been almost seen. There are problems with S and AV charmed mesons like D*s0(2317), Ds1(2460) : their nature and structure are not clear. Single b-mesons have almost similar situation.

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5- Except spin 3/2 Ω*

b all single b-baryons have been discovered. Experiments are looking for corresponding resonances. In 23 May 2018 the LHCb Collaboration reported observation of Ξb(6227). 6- Charmonium and bottomonium spectrum should be clarified. Some new states containing c cbar and b bbar should be clarified whether they are quarkonia or exotic states. 7- Only Ξcc as doubly charmed baryon has been seen. (Tension between SELEX and LHCb data) 8- No doubly-bottom as well as triply charmed/bottom baryons have been discovered yet.

LHCb: Σb±(6097) - 20 Sep 2018

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Recent progresses on the standard hadrons: some examples

arXiv:1805.09384 [hep-ex]

23 May 2018

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Considering the properties of the particle from the experiment:

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The method: QCD Sum Rules

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By performing four-integrals over x we go to the momentum space.

Asian Side Hadronic Side

European Side OPE Side

Borel transf.: to suppress the contr. of higher states and cont

Continuum subtraction & quark hadron duality assumption

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Comparison with

Experimental data

13/06/19 14 Eur.Phys.J. C78 (2018) no.11, 894

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Theory

Experimental Width

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The LHCb could not fix their quantum numbers !!!!!!!! 13/06/19 18

Interpretation via mass and width:

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Our interpretation ( determination of JPC)

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We predicted the mass and width of their b-partners: S. S. Agaev, K. Azizi, H. Sundu, EPL 118 (2017) 61001.

The LHCb May searche for the b-states.

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We have made a good progress on exotic states both experimentally and theoretically, specially since 2003 when the tetraquark condidate X(3872) discovered by Belle.

Despite a lot of efforts, their nature and internal structure remains unclear:

Different models with different internal quark-gluon organization assumptions give consistent mass and width results with the experimental data !!!!!!

We shall further study these states and their electromagnetic, weak and strong interactions with other known particles.

Exotic or non-conventional states:

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Famous Candidates: X (3872): 2003 Belle DsJ(2632): 2004 Fermilab SELEX Z(4430): 2007 Belle Y(4140) : 2009 Fermilab, 2012 CMS, 2013 D0, Belle did not found, LHCb confirmed Zc(3900): 2013 BESIII, Belle Z(4430):2014 LHCb X(5568): February 2016 D0, LHCb, CMS and ATLAS did not found. X(4274), X(4500) and X(4700): June 2016 LHCb

Tetraquarks: diquark-antidiquark, meson molecules

More than 25 States!

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Pentaquarks:

4 quark-1 antiquark Baryon-Meson Molecule

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LHCb Pentaquarks, 2015: Pc (4380) and Pc(4450)

R. Aaij et al. [LHCb Collaboration], Phys. Rev. Lett.115, 072001 (2015).

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LHCb Pentaquarks, 2015

We consider them as meson-baryon molecul

admixture of

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Exp. data

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Phys. Rev. D 96, 094030 (2017)

The LHCb searches for these states, as well.

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v  New physics effects: LFUV

Deviations of the Exp. Data from SM predictions: up to 3.9 σ à important indications for NP

World Exp. average:

SM:

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SM pred.:

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arXiv:1904.08267 [hep-ph]; Accepted by PRD

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supports the present tension between SM theory predictions and experiment.

Experimental measurements on R(ηc) may provide valuable information on the possible lepton universality violation in Bc → ηclν channel.

Our prediction:

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Different new physics (NP) models have been proposed to explain these deviations: some model-independent approaches, charged Higgs, lepton flavor violating models, supersymmetric extension of the Standard Model with local gauged baryon and lepton numbers (BLMSSM), models with new gauge bosons, exotic quarks and exotic leptons and different Leptoquark Models,…

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arXiv:1708.08951 [hep-ph]

v  S-Hexaquark (uuddss): a candidate for dark matter?

Absolutely stable

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For mass in the 1.5-1.8 GeV range: The observed DM relic abundance and the observed DM to ordinary matter ratio can emerge naturally. Dark matter freezes out before primordial nucleosynthesis and does not significantly impact primordial abundances, so the conventional argument that DM is non-baryonic does not apply.

PoS ICRC2017 (2018) 929

arXiv:1711.10971 [hep-ph]

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arXiv:1904.09913 [hep-ph]: Submitted to PRL

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With 1.2 GeV mass: S is an absolutely stable particle: Thus a potential candidate for DM

S-hexaquark produces the desired cosmological DM abundance: DM/matter

Existence of this state seems contradicts to stability of oxygen nuclei !

Summary and concluding remarks: ✔ We have made a good progress in identification of the standard hadrons and understanding their properties. The nature of some newly discovered resonances are not clear. We may look for further resonances (doubly-triply heavy, …) , especially in charm sector. ✔ There have been good progresses on the properties of the exotics, however, the nature and internal quark organizations of most of them are under debates. ✔  There have been recorded significant deviations of Exp. data from SM predictions at some hadronic channels, recently. ✔ It is possible to search for DM and DE in QCD 13/06/19 43

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Thank You