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Register a new userHQEFT as A Large Component QCD and Comments on The Incompleteness of HQET
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The Heavy quark effective field theory (HQEFT) is revisited in a more intuitive way. It is shown that HQEFT is a consistent large component QCD of heavy quarks. In the non-relativistic limit, HQEFT recovers the non-relativistic QCD (NRQCD). The resulting new effects in the HQEFT of QCD are carefully reexamined. It is then natural to come to the comments on the usual heavy quark effective theory (HQET). Consistent phenomenological applications of HQEFT exhibit its interesting features and completeness in comparison with HQET. It then becomes manifest why we shall base on the HQEFT of QCD rather than HQET which is an incomplete one for computing 1/m_Q corrections. More precise extraction for |V_{cb}| and |V_{ub}| in the HQEFT of QCD is emphasized.
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The more precise extraction for the CKM matrix element |V_{cb}| in the heavy quark effective field theory (HQEFT) of QCD is studied from both exclusive and inclusive semileptonic B decays. The values of relevant nonperturbative parameters up to order 1/m^2_Q are estimated consistently in HQEFT of QCD. Using the most recent experimental data for B decay rates, |V_{cb}| is updated to be |V_{cb}| = 0.0395 pm 0.0011_{exp} pm 0.0019_{th} from Bto D^{ast} l u decay and |V_{cb}| = 0.0434 pm 0.0041_{exp} pm 0.0020_{th} from Bto D l u decay as well as |V_{cb}| = 0.0394 pm 0.0010_{exp} pm 0.0014_{th} from inclusive Bto X_c l u decay.
The graviton solutions for the glueball spectrum of ref. cite{Rinaldi:2017wdn} interpreted in a different manner lead to very interesting results which we describe in this comment.
There are no three regimes of QCD, as speculated in that paper. There are only two, separated by already well known $T_csim 155, MeV$. Above it electric interactions are screened rather then confined. Magnetic ones remain confined all the way to $Trightarrow infty$. Spectrum of mesonic screening masses is there, but they do not represent real masses. At high $T$ they correspond to heavy quarkonia of 2+1 d gauge theory, which is well known to be a confining theory. There is no reason to expect any transition unbinding them, at $Tsim 1, GeV$ as claimed. I make calculation of correction to screening masses in 2+1d at high temperature including spatial screening tension and find results in agreement with recent lattice data.
The QCD/HQET matching coefficient for the heavy-quark field is calculated up to four loops. It must be finite; this requirement produces analytical results for some terms in the four-loop on-shell heavy-quark field renormalization constant which were previously only known numerically. The effect of a non-zero lighter-flavor mass is calculated up to three loops. A class of on-shell integrals with two masses is analyzed in detail. By specifying our result to QED, we obtain the relation between the electron field and the Bloch--Nordsieck field with four-loop accuracy.
In his recent Comments E. Shuryak reiterates old, unfortunately misleading arguments in favor of deconfined Quark-Gluon Plasma (QGP) immediately above the chiral restoration pseudocritical temperature. In a Comment devoted to our view of QCD at high temperatures he does not address and even mention the essence of our arguments. In recent years a new hidden symmetry in QCD was discovered. It is a symmetry of the electric sector of QCD, that is higher than the chiral symmetry of the QCD Lagrangian as the whole. This symmetry was clearly observed above T_c in spatial correlators and very recently also in time correlators. The latter correlators are directly related to observable spectral density. Then in a model-independent way we conclude that degrees of freedom in QCD above T_c, but below roughly 3T_c, are chirally symmetric quarks bound by the chromoelectric field into color-singlet compounds without the chromomagnetic effects. This regime of QCD has been referred to as a Stringy Fluid since such objects are very reminiscent of strings.At higher temperatures there is a very smooth transition to the partonic degrees of freedom, i.e. to the QGP regime. Here we will address some of the points made by Shuryak.
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