Observation of the Higgs Boson of strong interaction via Compton scattering by the nucleon

The European Physical Journal C, May 2010

It is shown that the Quark-Level Linear σ Model (QLLσM) leads to a prediction for the diamagnetic term of the polarizabilities of the nucleon which is in excellent agreement with experimental data. The bare mass of the σ meson is predicted to be m σ =666 MeV and the two-photon width Γ(σ→γ γ)=(2.6±0.3) keV. It is argued that the mass predicted by the QLLσM corresponds to the \(\gamma\gamma\to\sigma\to N\bar{N}\) reaction, i.e. to a t-channel pole of the γ N→N γ reaction. Large-angle Compton scattering experiments revealing effects of the σ meson in the differential cross section are discussed. Arguments are presented that these findings may be understood as an observation of the Higgs boson of the strong interaction while being a part of the constituent quark.

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Observation of the Higgs Boson of strong interaction via Compton scattering by the nucleon

Martin Schumacher 0 0 Zweites Physikalisches Institut der Universitt Gttingen , Friedrich-Hund-Platz 1, 37077 Gttingen, Germany It is shown that the Quark-Level Linear Model (QLL M) leads to a prediction for the diamagnetic term of the polarizabilities of the nucleon which is in excellent agreement with experimental data. The bare mass of the meson is predicted to be m = 666 MeV and the twophoton width ( ) = (2.6 0.3) keV. It is argued that the mass predicted by the QLL M corresponds to the N N reaction, i.e. to a t -channel pole of the N N reaction. Large-angle Compton scattering experiments revealing effects of the meson in the differential cross section are discussed. Arguments are presented that these findings may be understood as an observation of the Higgs boson of the strong interaction while being a part of the constituent quark. 1 Introduction The meson introduced by Schwinger [1] and Gell-Mann Levy [2] has attracted great interest because there are good reasons to consider it as the Higgs boson of strong interaction, an aspect which recently has been emphasized by several authors [36]. The mass of the meson is predicted by the Quark-Level Linear Model (QLL M) [7, 8] (see also [911] and references therein) to be m = 666 MeV, whereas scattering analyses led to s = M i /2 with M = 441+16 MeV and = 544+1285 MeV in one re8 cent evaluation (CCL) [12], or s = (476 628) i(226 346) MeV when tests of the stability of fits to data are taken into account [13]. It certainly is extremely important to understand how these two masses are related to each other. The finding is that m = 666 MeV is the bare mass of the meson which is observed in space-like Compton scattering N N , i.e. as a t -channel pole of Compton scattering N N . For the electromagnetic polarizabilities space-like Compton scattering is equally important as time-like Compton scattering N N (s-channel). The and non- components of the electromagnetic polarizabilities for the proton (p) and the neutron (n) are p,n( ) = p,n = 7.6, p(non- ) = 4.4, p(non- ) = 9.5, n(non- ) = 5.8, n(non- ) = 9.4 in units of 104 fm3. On the quark level the reaction N N implies that two photons with parallel planes of linear polarization interact with mesons, being parts of the constituent quarks. In this sense it is justified to consider space-like Compton scattering as an in-situ observation of the Higgs boson of strong interaction. In addition to the specific aspects of the meson as outlined in the preceding paragraph this particle is of interest because it has been observed as an intermediate state in many reactions [14]. Therefore, there is no doubt that this particle exists and that it belongs to a scalar nonet ( (600), f0(980), a0(980), (800)) below 1 GeV. A problem may appear due to the fact that there is also a scalar nonet above 1 GeV. This has led to the assumption that the scalar nonet above 1 GeV should be understood as qq states whereas the scalar nonet below 1 GeV should be understood as qqq q states (see e.g. [4] and references therein). Other versions consider meson molecules and gluonic components (see [3 6, 1518] and references therein). It is hard to see that strict criteria can be found giving proof of the validity of one model and excluding the validity of an other. The best way to proceed is to start with a model for the low-mass scalar mesons where qq is a 3P0 core state which may couple to other hadronic or gluonic configurations [17]. Then the essential properties as e.g. the two-photon width ( ) may be understood in terms of the qq core whereas other components may show up in hadronic reactions where scalar mesons appear as intermediate states. The present work is a continuation of a systematic series of studies [9, 10, 1922] on the electromagnetic structure of the nucleon, following experimental work on Compton scattering and a comprehensive review on this topic [23]. These recent investigations have shown [9, 10, 1922] that a systematic study of all partial resonant and nonresonant photoexcitation processes of the nucleon and of their relevance for the fundamental structure constants of the nucleon as there are the electric polarizability (), the magnetic polarizability () and the backward spin-polarizability ( ) is essential for an understanding of the electromagnetic structure of the nucleon. In addition it has been found that the structure of the constituent quarks and their coupling to pseudoscalar and scalar mesons is important for the understanding of the electric and magnetic polarizabilities and of the backward spin-polarizability. The main purpose of the present work is to prove that the method of calculating the t -channel contribution from the reaction N N where the properties of the meson are taken from the QLL M is a precise procedure and largely superior to previous approaches where the combination of the two reactions and N N is exploited. 2 The dynamical (...truncated)


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Martin Schumacher. Observation of the Higgs Boson of strong interaction via Compton scattering by the nucleon, The European Physical Journal C, 2010, pp. 283-293, Volume 67, Issue 1-2, DOI: 10.1140/epjc/s10052-010-1290-x