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The road map in this research proves that the universe emerged from SUSY. Proving that, we link between two different classes of SM, fermions, and bosons in supersymmetry with their properties in the Standard Model of particle physics. According to SM properties, the bosons have spin one, while fermions have spin 1/2. We suggest differentiating between bosons and fermions angular momentum in our real world with a supersymmetrical state. We presume that bosons and fermions in their supersymmetric environment will have akin graviton spin angular momentum 2, while their superpartners will have spin one. In addition to that, in the supersymmetric environment, the fermion, boson, and their counterparts experience CPT conservation. They enjoy eternity with "Gravitons." Once upon a time, the boson and fermion descended from a supersymmetric state down through string theories' dimensions and M-theory's branes, stabilizing and forming SM quarks and, therefore, everything in our real world

The elegant concept of isospin symmetry is of fundamental importance in nuclear and elementary particle physics. As a β-decay process changes an up quark to a down quark or vice versa , studies of nuclei with exchanged numbers of neutrons and protons, known as mirror nuclei, can be a powerful means to probe isospin symmetry breaking. A series of β-decay experiments of sd-shell nuclei near the proton drip line produced by projectile fragmentation were performed at the Radioactive Ion Beam Line of the Heavy Ion Research Facility in Lanzhou (HIRFL-RIBLL1) using a silicon array with a high detection efficiency and a low detection threshold. The secondary ions were identified by the combination of Δ E -TOF and magnetic rigidity ( Bρ ) in which the time of flight (TOF) was measured by two plastic scintillators at the second and fourth focal planes of the RIBLL1 and the energy loss (Δ E ) was measured by two silicon detectors in the front of the silicon array. Double-sided silicon strip detectors (DSSDs) in the center of the array served to measure the residual energies of secondary ions on an event-by-event basis and study their decay properties with an implantation-decay correlation. Several quadrant silicon detectors (QSDs) placed behind DSSDs were used for anticoincidences of the penetrating fragments and light particles coming along with the beam, and measurements of β particles and high-energy protons. The β-delayed proton peaks with known energies and their corresponding absolute intensities were used for the energy and detection efficiency calibrations of the DSSDs. The system allows us to measure protons with energies down to about 200 keV without obvious β background in the proton spectrum and was successful to measure the energies, time, and positions of implanted ions and decay protons efficiently, supporting researchers to study the decay properties of nuclei towards the proton drip line. The β-decay data, together with the large-scale shell-model calculations, allows detailed investigations on the mirror-nuclei systems resulting in the systematic study of isospin symmetry breaking in the sd-shell nuclear region. It was found that the mirror asymmetry parameters become larger due to the smaller separation energies while approaching the proton drip line for the extremely proton-rich sulfur nuclei 27,28,29S and the Coulomb forces and other isospin-symmetry nonconserving forces acting between protons would lead to extended proton wave functions and cause mirror asymmetries. The properties of 22Si β-decay for the transitions to the low-lying states of 22Al were measured, and the reduced transition probabilities were determined. Comparing with the data on the β-decay of the mirror nucleus 22O, we found a mirror asymmetry of δ =209(96)% in the transition to the first 1+ excited state of the respective daughters. This is by far the largest value of δ observed in the low-lying states. Shell-model calculations with isospin-nonconserving forces, including the T =1, J =2, 3 interactions related to the s1/2 orbit that introduces explicitly the isospin-symmetry breaking force and describes the loosely bound nature of the wave functions of the s1/2 orbit, can reproduce the observed data well and demonstrate that this dramatically large mirror asymmetry is attributed to the significant proton occupation and loosely bound nature of the wave functions of the s1/2 orbit, which suggests that 22Al is a proton-halo nucleus.

If most of the universe is made of baryons, we encounter a serious contradiction in explaining the observed structure formulation. Therefore, we need non-baryonic dark matter to comprise the universe. In a previous paper, the present author proposed an infinite sub-layer quark model in which there exists an infinite number of up quark qu (∞) and down quark qd (∞) at an infinite sub-layer level. These quarks have non-baryon quantum number with one-half electric charge. Thus, qu (∞) and qd (∞) quarks are candidates for the non-baryonic dark matter. It is then shown that CP is violated only in the doublet of qu (∞) and qd (∞) quarks to account for the asymmetry of the number of particles and anti-particles in the present universe. It should be emphasized that if the internal space of qu (∞) and qd (∞) quarks in the first generation is a noncommutative geometry, CP violation can be explained without increasing the number of particles and generations. Thus, a pair of an infinite number of qu (∞) and qd (∞) quarks would be produced in the first moments after the Big Bang and form the hadrons including the nucleons and remain as the non-baryonic cold dark matter for all time. From the qf (∞) quarks with the flavors f = u, d, s, c, t, and b, we compared our prediction value of the cross-section ratio R with the experimental values. We obtained the theoretical branching ratio R = 15/4 = 3.75 which is in good agreement with the experimental values from 12.00 GeV to 46.47 GeV in electron-positron annihilation into muon pairs and quark pairs.

Due to the absence of the free neutron target, the form factors or the structure function of the neutron directly cannot be obtained from the elastic scattering data. Therefore, in this paper, we obtained the neutron structure function using the deep inelastic structure function of the proton and by applying the EMC and the shadowing effects on the structure function of the deuteron. Then, using the quantum chromo dynamics theorem and re-analysis of data from the SLAC experiments E49, E61, E87, and E89 in electron–proton deep inelastic scattering at Q2 = 1–20 GeV2, we have extracted the up and down quark distribution functions, $${{u}_{{v}}}$$ (x), $${{d}_{{v}}}$$ (x), and also, using an appropriate model for the general parton distribution function, we have plotted the Dirac form factor of the neutron. At the end, the curves obtained in this work were compared with the curves obtained in other models.

In this paper we study the impact of ATLAS 8 TeV t-channel single top quark production data on CT14nnlo PDFs. First, we calculate the total cross section, cross section ratio, differential cross section, and normalized differential cross section as a function of transverse momentum pT and rapidity y, at next-to-leading order QCD by MadGraph using CT14nnlo PDFs. And then we update CT14nnlo PDFs and observables by applying Error PDF Updating method. We find that down quark PDF increased roughly about 3% in 10− 4 < x

The paper briefly studies the interaction between an electron and a down quark, considered integrated within a proton. It is therefore assumed that there is a down quark within a proton in which there are also two quarks up and an accelerated electron capable of penetrating the down quark inside the proton, in extremely difficult conditions in which the proton is already accelerated to a certain level necessary to start the nuclear fusion reaction between two hydrogen protons, in which case a proton already has high kinetic energy, moving at a very high linear velocity and having an extremely small size. Under these conditions, the possibility is studied for an electron to penetrate the proton, or more precisely to be able to interact (to be able to join) the down quark. It determines the kinetic energy required for the electron to achieve a goal like this.

The paper briefly examines the possibility of transforming a proton into a neutron, by introducing an accelerated electron inside the proton, in order to penetrate it into one of the two up quarks in order to transform it into a down quark, thus transforming the initial state of the proton into a new state of a neutron. Such an achievement can be extremely important in the nuclear fusion energy industry, but also in many other energy fields. It is easy to see that an accelerated electron can penetrate a proton in order to transform it into a neutron if the minimum kinetic energy of the penetrating by the accelerating electron is between the values of (10-103 [MeV]).

We study quark flavor violating interactions mediated by the Higgs boson $h$. We consider observables involving a third generation quark, of both the up and the down quark sectors, like $h\rightarrow bs$ and $t\rightarrow ch$. Using an effective field theory approach we systematically list all the possible tree-level ultraviolet completions, which comprise models with vector-like quarks and/or extra scalars. We provide upper bounds on the flavor violating transitions allowed by current limits stemming from low energy processes, such as meson mixing and $b \rightarrow s \gamma$. We find that scenarios with vector-like quarks always have very suppressed flavor-violating transitions, while a general two Higgs doublet model may have a sizeable rate. To study the latter case in detail, we perform a full numerical simulation taking into account all relevant theoretical and phenomenological constraints. Our results show that ${\rm BR}(t\rightarrow ch)$ [${\rm BR}(h\rightarrow bs)$] are still allowed at the subpercent [percent] level, which are being [may be] explored at the LHC [future colliders]. Finally, we have found that the mild mass-splitting discrepancy with respect to the SM in the $B_s$ meson system can be accommodated in the Two-Higgs-Doublet Model. If confirmed, it yields the prediction ${\rm BR}(h\rightarrow bs)\simeq 10^{-4}$, if the new contribution to the mass-splitting is dominated by tree-level Higgs boson exchange., Comment: 38 pages, 13 figures, 9 tables

We produce the light-front wave functions (LFWFs) of the nucleon from a basis light-front approach in the leading Fock-sector representation. We solve for the mass eigenstates from a light-front effective Hamiltonian, which includes a confining potential adopted from light-front holography in the transverse direction, a longitudinal confinement, and a one-gluon exchange interaction with fixed coupling. We then employ the LFWFs to obtain the electromagnetic and axial form factors, the parton distribution functions (PDFs), and the generalized parton distribution functions for the nucleon. The electromagnetic and axial form factors of the proton agree with the experimental data, whereas the neutron form factors deviate somewhat from the experiments in the low-momentum transfer region. The unpolarized, the helicity, and the transversity valence quark PDFs, after QCD scale evolution, are fairly consistent with the global fits to the data at the relevant experimental scales. The helicity asymmetry for the down quark also agrees well with the measurements; however, the asymmetry for the up quark shows a deviation from the data, especially in the small x region. We also find that the tensor charge agrees well with the extracted data and the lattice QCD predictions, while the axial charge is somewhat outside the experimental error bar. The electromagnetic radii of the protons, the magnetic radius of the neutron, and the axial radius are in excellent agreement with the measurements, while the neutron charge radius deviates from the experiment.

We present lattice QCD results for masses and magnetic polarizabilities of light and strange pseudoscalar mesons, chiral condensates, decay constants of neutral pion, and neutral kaon in the presence of background magnetic fields with $eB$ ranging up to around 3.35 GeV$^2$ ($\sim70~M_\pi^2$) in the vacuum. The computations were carried out in (2+1)-flavor QCD mostly on $32^3 \times 96$ lattices using the highly improved staggered quark action with $M_{\pi} \approx $ 220 MeV at zero temperature. We find that the masses of neutral pseudoscalar mesons monotonously decrease as the magnetic field strength grows and then saturate at a nonzero value, while there exists a nonmonotonous behavior of charged pion and kaon masses in the magnetic field. We observe a $qB$ scaling of the up and down quark flavor components of neutral pion mass, neutral pion decay constant as well as the quark chiral condensates at 0.05 $\lesssim eB\lesssim$ 3.35 GeV$^2$. We show that the correction to the Gell-Mann-Oakes-Renner relation involving the neutral pion is less than 6% and the correction for the relation involving neutral kaon is less than 30% at $eB\lesssim$ 3.35 GeV$^2$. We also derive the Ward-Takahashi identities for QCD in the magnetic field in the continuum formulation including the relation between integrated neutral pseudoscalar meson correlators and chiral condensates., Comment: 30 pages, 18 figures, updated to the published version in PRD

We use the nCTEQ analysis framework to investigate nuclear parton distribution functions (nPDFs) in the region of large $x$ and intermediate-to-low $Q$, with special attention to recent JLab deep inelastic scattering data on nuclear targets. This data lies in a region which is often excluded by $W$ and $Q$ cuts in global nPDF analyses. As we relax these cuts, we enter a new kinematic region, which introduces new phenomenology. In particular, we study the impact of (i) target mass corrections, (ii) higher twist corrections, (iii) deuteron corrections, and (iv) the shape of the nuclear PDF parametrization at large-$x$ close to one. Using the above tools, we produce a new nPDF set (named nCTEQ15HIX) which yields a good description of the new JLab data in this challenging kinematic region, and displays reduced uncertainties at large $x$, in particular for up and down quark flavors.

We demonstrate that multiple-Higgs production at the LHC is the most sensitive probe of first- and second-generation quark flavor in the Higgs sector. In models where new scalars couple to light quarks, gigantic di-Higgs and even sizable tri-Higgs production rates can be obtained, which can be used to either discover or severely constrain such theories. As an example, we show that the most stringent bounds on enhanced interactions of the 125 GeV Higgs to the down quark in extended Higgs sectors are obtained by looking for the extra Higgs bosons that provide for such enhancements using the di-Higgs and Zh topologies. In this context, we set new limits on the 125 GeV Higgs coupling to the down quark as strong as λhdd¯≲20λhdd¯SM—a dramatic improvement over previously available bounds. Regarding second-generation quark flavor, we obtain new limits in the coupling to strange as strong as λhss¯≲10λhss¯SM. In addition, we show that the currently unexplored triple-Higgs production topology could be a potential discovery channel of a wide variety of extended Higgs sectors at the LHC, including not only models where extra Higgses couple to light quarks, but also more frequently studied theories where they have preferential couplings to the top.

In this work, we determine up/down-quark mass $m_{q=u/d}$ in the isoscalar scalar channel from both the Shifman-Vainshtein-Zakharov (SVZ) and the Monte-Carlo-based QCD sum rules. The relevant spectral function, including the contributions from the $f_0(500)$, $f_0(980)$ and $f_0(1370)$ resonances, is determined from a sophisticated $U(3)$ chiral study. Via the traditional SVZ QCD sum rules, we give the prediction to the average light-quark mass $m_q(2 \, \text{GeV})=\frac{1}{2}(m_u(2 \, \text{GeV}) + m_d(2 \, \text{GeV}))=(3.46^{+0.16}_{-0.22} \pm 0.33) \, \text{MeV}$. Meanwhile, by considering the uncertainties of the input QCD parameters and the spectral functions of the isoscalar scalar channel, we obtain $m_q (2\, \text{GeV}) = (3.44 \pm 0.14 \pm 0.32) \, \text{MeV}$ from the Monte-Carlo-based QCD sum rules. Both results are perfectly consistent with each other, and nicely agree with the Particle Data Group value within the uncertainties., 25 pages,7 figures,2 tables

We calculate the leading-twist helicity-dependent generalized parton distributions (GPDs) of the proton at finite skewness in the Nambu--Jona-Lasinio (NJL) model of quantum chromodynamics (QCD). From these (and previously calculated helicity-independent GPDs) we obtain the spin decomposition of the proton, including predictions for quark intrinsic spin and orbital angular momentum. The inclusion of multiple species of diquarks is found to have a significant effect on the flavor decomposition, and resolving the internal structure of these dynamical diquark correlations proves essential for the mechanical stability of the proton. At a scale of ${Q}^{2}=4$ ${\mathrm{GeV}}^{2}$ we find that the up and down quarks carry an intrinsic spin and orbital angular momentum of ${S}_{u}=0.534$, ${S}_{d}=\ensuremath{-}0.214$, ${L}_{u}=\ensuremath{-}0.189$, and ${L}_{d}=0.210$, whereas the gluons have a total angular momentum of ${J}_{g}=0.151$. The down quark is therefore found to carry almost no total angular momentum due to cancellations between spin and orbital contributions. Comparisons are made between these spin decomposition results and lattice QCD calculations.

In this paper a “non-elementary system” is defined as a system consisting of elementary (i.e., indivisible) constituents. Such systems are a common feature of the standard model of particle physics: for example, according to the standard model, a proton (non-elementary particle) consists of two up quarks and one down quark (elementary particles). However, the definition of elementary constituent may be loosened, depending on the phenomenon that is investigated and on the model used to represent it: in an α-decay process, a proton can be considered as an elementary constituent of an α-particle; in much the same way, in elemental analysis an atom can be considered as an elementary constituent of a molecule, even if the atom is made up of nucleons.

We have studied the lepton and quark mixing patterns which can be derived from the dihedral group $D_n$ in combination with CP symmetry. The left-handed lepton and quark doublets are assigned to the direct sum of a singlet and a doublet of $D_n$. A unified description of the observed structure of the quark and lepton mixing can be achieved if the flavor group $D_n$ and CP are broken to $Z_2\times CP$ in neutrino, charged lepton, up quark and down quark sectors, and the minimal group is $D_{14}$. We also consider another scenario in which the residual symmetry of the charged lepton and up quark sector is $Z_2$ while $Z_2\times CP$ remains preserved by the neutrino and down quark mass matrices. Then $D_7$ can give the experimentally favored values of CKM and PMNS mixing matrices., 22 pages, 3 figures

The QCD up- and down-quark masses are determined from an optimized QCD Finite Energy Sum Rule (FESR) involving the correlator of axial-vector current divergences. In the QCD sector this correlator is known to five loop order in perturbative QCD (PQCD), together with non-perturbative corrections from the quark and gluon condensates. This FESR is designed to reduce considerably the systematic uncertainties arising from the hadronic spectral function. The determination is done in the framework of both fixed order and contour improved perturbation theory. Results from the latter, involving far less systematic uncertainties, are: $\bar{m}_u (2\, \mbox{GeV}) = (2.6 \, \pm \, 0.4) \, {\mbox{MeV}}$, $\bar{m}_d (2\, \mbox{GeV}) = (5.3 \, \pm \, 0.4) \, {\mbox{MeV}}$, and the sum $\bar{m}_{ud} \equiv (\bar{m}_u \, + \, \bar{m}_d)/2$, is $\bar{m}_{ud}({ 2 \,\mbox{GeV}}) =( 3.9 \, \pm \, 0.3 \,) {\mbox{MeV}}$., A Mathematica^(C) file pertaining to numerical evaluations is attached as Ancillary

Hiçyılmaz, Yaşar (Balikesir Author), dsf, We have studied phenomenological implications of several family non-universal U(1)' sub-models in the U(1)'-extended Minimal Supersymmetric Standard Model (UMSSM) possessing an extra down quark type exotic field. In doing this, we have started by enforcing anomaly cancellation criteria to generate a number of solutions in which the extra U(1)' charges of the particles are treated as free parameters. We have then imposed existing bounds coming from colliders and astrophysical observations on the assumed sub-models and observed that current limits dictate certain charge orientations, for instance, QH(u) similar to QH(d) is preferred in general and the charge of the singlet Q(S) cannot be very small (vertical bar Q(S)vertical bar > 0.4) even if any of the charges is allowed to take any value within the [-1, 1] range. We have finally studied the potential impact of such non-universal charges on Z' mediated processes and made predictions for existing and future experiments. It has turned out that UMSSMs with or without the presence of light exotic quarks can yield distinguishable signatures if non-universal charges are realised in the leptonic sector of such models, NExT Institute UK Research & Innovation (UKRI) Science & Technology Facilities Council (STFC) ST/L000296/1

Rare B meson decays offer an opportunity to probe a light hidden Z ′ boson. In this work we explore a new channel B q → γ Z ′ ( q = d , s ) followed by a cascade decay of Z ′ into an invisible (neutrino or dark matter) or charged lepton pair l + l − ( l = e , μ ). The study is based on a simplified effective model where the down quark sector has tiny flavor-changing neutral current couplings with Z ′ . For the first time, we calculate BR ( B q → γ Z ′ ) at the leading power of 1 / m b and 1 / E γ . Confronting with the strong constraints from semi-invisible decays of B meson, we find that the branching ratio for B d → invisible + γ can be larger than its Standard Model background prediction, leaving a large room for new physics, in particular for light dark matter. Additionally, the branching ratio for B d → e + e − γ can also be sizable when the corresponding flavor violating Z ′ coupling to quarks is of the axial-vector type. On the other hand, the predicted branching ratios of B d → μ + μ − γ and B s → l + l − γ are severely constrained by the experimental measurements.

We investigate the quark number fluctuations up to the fourth order in the matter composed of two light flavor quarks with isospin symmetry and at finite temperature and finite chemical potential using the Dyson-Schwinger equation approach of QCD. In order to solve the quark gap equation, we approximate the dressed quark-gluon vertex with the bare one and adopt both the Marris-Tandy (MT) model and the infrared constant (Qin-Chang) model for the dressed gluon propagator. Our results indicate that the second, third, and forth order fluctuations of net quark number all diverge at the critical end point (CEP). Around the CEP, the second order fluctuation possesses obvious pump while the third and fourth order ones exhibit distinct wiggles between positive and negative. For the MT model and the Qin-Chang model, we give the pseudo-critical temperature at zero quark chemical potential as $T_{c}=146$ MeV and $150$ MeV, and locate the CEP at $({\mu_{E}^{q}}, {T_{E}^{}}) = (120, 124)$ MeV and $(124,129)$ MeV, respectively. In addition, our results manifest that the fluctuations are insensitive to the details of the model, but the location of the CEP shifts to low chemical potential and high temperature as the confinement length scale increases., Comment: 10 pages, 6 figures

Rare B meson decays induced by flavour-changing neutral current (FCNC) transition play the most promising role to probe the flavour sector of the standard model (SM). Basically, FCNC processes are forbidden at the tree level in SM and will arise from loop diagrams which are generally suppressed in comparison to tree diagrams. This provides an excellent testing ground for NP. On the basis of various experimental studies, it is found that the FCNC processes having quark-level transition \(b\to s\) are challenging because of their small branching ratio (\(\mathcal{O}\left({10}^{-6}\right)\). So we would like to study such a type of semileptonic rare B decay mode \({B}_{s}\to \varphi {\mu }^{+}{\mu }^{-}\) involving the quark-level transition \(b\to s{l}^{+}{l}^{-}\left(l=\mu \right)\). Here, we analyse the effect of non-universal Z boson in the differential decay rate of the decay mode \({B}_{s}\to \varphi {\mu }^{+}{\mu }^{-}\). The non-universal Z model is a simple model beyond the SM with an extended matter sector due to an additional vector-like down quark, as a consequence of which it allows the CP-violating Z-mediated FCNC process at the tree level. We find a significant deviation of the differential decay rate for this decay \({B}_{s}\to \varphi {\mu }^{+}{\mu }^{-}\) from the SM value because of non-universal \(Z-bs\) coupling.

The finite, non-zero mean square neutron charge radius is understood in the present work to have a topological origin from an intrinsic neutron configuration in the Lie group U(3). We introduce up and down quark orbits in the configuration for the neutron mass eigenstate. From reciprocal Gaussian curvatures we infer a mean square charge radius of −0.1075 square fermis a few standard deviations away from the world average of −0.1161 square fermis.

Quark matter with only $u$ and $d$ quarks ($ud$QM) might be the ground state of baryonic matter at large baryon number $A>A_{\rm min}$. With $A_{\rm min}\gtrsim 300$, this has no direct conflict with the stability of ordinary nuclei. An intriguing test of this scenario is to look for quantum nucleation of $ud$QM inside neutron stars due to their large baryon densities. In this paper, we study the transition rate of cold neutron stars to $ud$ quark stars ($ud$QSs) and the astrophysical implications, considering the relevant theoretical uncertainties and observational constraints. It turns out that a large portion of parameter space predicts an instantaneous transition, and so the observed neutron stars are mostly $ud$QSs. We find this possibility still viable under the recent gravitational wave and pulsar observations, although there are debates on its compatibility with some observations that involve complicated structure of quark matter. The tension could be partially relieved in the two-families scenario, where the high-mass stars ($M\gtrsim2 M_{\odot}$) are all $ud$QSs and the low-mass ones ($M\sim1.4\, M_{\odot}$) are mostly hadronic stars. In this case, the slow transition of the low-mass hadronic stars points to a very specific class of hadronic models with moderately stiff EOSs, and $ud$QM properties are also strongly constrained., 26 pages, 11 figures

In this paper we perform the first simultaneous QCD global analysis of data from semi-inclusive deep inelastic scattering, Drell-Yan, $e^+e^-$ annihilation into hadron pairs, and proton-proton collisions. Consequently, we are able to extract a universal set of non-perturbative functions that describes the observed asymmetries in these reactions. The outcome of our analysis indicates single transverse-spin asymmetries in high-energy collisions have a common origin. Furthermore, we achieve the first phenomenological agreement with lattice QCD on the up and down quark tensor charges., Comment: 8 pages, 6 figures, matches published version

The proposed structures of stable nuclei of H-1 through Li-7 incorporate an alternating up and down quark sequence (AQS) of equally spaced quarks around regular geometries. AQS nuclear models represent quark positions in the same way molecular ball and stick models represent the relative positions of atoms. In AQS, the ball identifies the center of quark mass and the stick length is constant and equal to the most recent radius of the proton (0.8414 fm). AQS radius predictions use accepted quark masses where necessary, and predictions demonstrate 99.3% average agreement (SD 4%) and statistical correlation of ρ = 0.96, p

We present a new approach to parton distributions based on light-front holography and Veneziano duality. In this framework, parton distributions can be determined up to a universal reparametrization function $w(x)$, which is highly constrained by boundary conditions. The Regge behavior at small $x$ and the perturbative QCD counting rule at large $x$ are reproduced. Furthermore, unpolarized and polarized distributions are strictly related by the chirality separation from the holographic Lagrangian. It allows us to predict polarized distributions from unpolarized distributions without adding free parameters. The numerical results agree with existing experimental data and the perturbative QCD helicity retention prediction at $x\to1$ limit, and particularly, the down quark polarized distribution is predicted to change sign around $x\sim0.8$. This predictions bears minimal theoretical uncertainty and can be tested soon in future JLab experiments.

We scrutinize the penguin dominated $ B_s \to K^+ K^-$ decay mode involving $b \to s$ quark level transition in family non-universal $Z^ \prime$ and vector-like down quark model. There is discrepancy in the standard model branching ratio value of this mode with the experimental results reported by Belle, CDF and LHCb Collaborations. Additionally, the measured values of CP-violating asymmetries $ C_{K^+K^-}$ and $ S_{K^+K^-}$ deviate from the SM results. We constrain the new parameter space by using the existing experimental limits on leptonic $ B_s\to \ell \ell$ ($\ell = e, \mu, \tau$) processes. We then check the effects of new physics on the branching ratio and CP violating parameters of the $ B_s \to K^+ K^-$ process.

Predicting the Bs0−B¯s0 width difference ΔΓs relies on the heavy quark expansion and on hadronic matrix elements of ΔB=2 operators. We present the first lattice QCD results for matrix elements of the dimension-7 operators R2,3 and linear combinations R˜2,3 using nonrelativistic QCD for the bottom quark and a highly improved staggered quark (HISQ) action for the strange quark. Computations use MILC Collaboration ensembles of gauge field configurations with 2+1+1 flavors of sea quarks with the HISQ discretization, including lattices with physically light up or down quark masses. We discuss features unique to calculating matrix elements of these operators and analyze uncertainties from series truncation, discretization, and quark mass dependence. Finally we report the first standard model determination of ΔΓs using lattice QCD results for all hadronic matrix elements through O(1/mb). The main result of our calculations yields the 1/mb contribution ΔΓ1/mb=−0.022(10) ps−1. Adding this to the leading order contribution, the standard model prediction is ΔΓs=0.092(14) ps−1.

We study the phenomenology of two leptoquarks, the Standard Model $SU(2)$ singlets $S_1$ and $U_1$, with regard to the latest experimental data from the low-energy flavor physics measurements, LHC, and the IceCube neutrino experiment. We consider a scenario when scalar (vector) leptoquark $S_1$ ($U_1$) couples exclusively to the down quark and the neutrinos (charged leptons) of all flavors, where the leptoquark in question couples to the SM lepton doublets. The couplings of $S_1$ ($U_1$) to the up-type quarks and the charged leptons (neutrinos) are in turn uniquely determined via $SU(2)$ symmetry. We find that the most important constraints on the leptoquark parameter space originate from flavor physics measurements, followed by the LHC search limits that take over the flavor physics ones in the large LQ mass regime. We furthermore show that $S_1$ ($U_1$) marginally improves (spoils) the fit of the current IceCube data with respect to the SM case within the region of parameter space that is otherwise consistent with various low-energy flavor physics measurements and the latest LHC input. Our study offers an up-to-date analysis for these two leptoquarks in view of the latest experimental data., Comment: 15 pages, 9 figures, modified version with the inclusion of the latest IceCube data

As there exist no repulsive forces in strong interaction, in a hypothetical approach, strong interaction can be assumed to be equivalent to a large gravitational coupling. Based on this concept, strong coupling constant can be defined as a ratio of the electromagnetic force and the gravitational force associated with proton, neutron, up quark and down quark. With respect to the product of strong coupling constant and fine structure ratio, we review our recently proposed two semi empirical relations and coefficients 0.00189 and 0.00642 connected with nuclear stability and binding energy. We wish to emphasize that- by classifying nucleons as ‘free nucleons’ and ‘active nucleons’, nuclear binding energy can be fitted with a new class of ‘three term’ formula having one unique energy coefficient. Based on the geometry and quantum nature, currently believed harmonic oscillator and spin orbit magic numbers can be considered as the lower and upper “mass limits” of quark clusters.

We explain all features of lepton and quark mixing in a scenario with the flavor symmetry Delta (384) and a CP symmetry, where these are broken in several steps. The residual symmetry in the neutrino and up quark sector is a Klein group and CP, while a Z_3 and a Z_{16} symmetry are preserved among charged leptons and down quarks, respectively. If the Klein group in the neutrino sector is further broken down to a single Z_2 symmetry, we obtain predictions for all lepton mixing parameters in terms of one real quantity, whose size is determined by the value of the reactor mixing angle. The Dirac and Majorana phases are fixed, in particular sin (delta) = -0.936. A sum rule, relating these CP phases and the reactor and atmospheric mixing angles, theta_{13} and theta_{23}, is given. In the quark sector, we have for the Cabibbo angle theta_C= sin (pi/16) = 0.195 after the first step of symmetry breaking. This is brought into full accordance with experimental data with the second step of symmetry breaking, where either the Z_{16} group is broken to a Z_8 symmetry in the down quark sector or the Klein group to one Z_2 symmetry only among up quarks. The other two quark mixing angles are generated in the third and last symmetry breaking step, when the residual symmetries in the up and/or down quark sector are further broken. If this step occurs among both up and down quarks, the amount of CP violation in the quark sector is determined by the lepton sector and explaining the current neutrino oscillation data entails that the Jarlskog invariant J_{CP}^q is in very good agreement with experimental findings. Lastly, a sum rule is derived that contains the CP phase delta^q and theta_C of the quark sector and the lepton mixing parameters theta_{13}, theta_{23} and delta., Comment: 12 pages, 1 figure, matches PRD version

The baryon form factor of charged pions arises since isospin symmetry is broken. We obtain estimates for this basic property in two phenomenological ways: from simple constituent quark models with unequal up and down quark masses, and from fitting to e+e−→π+π−data. All our methods yield a positive π+baryon mean square radius of (0.03 −0.04fm)2. Hence, a picture emerges where the outer region has a net baryon, and the inner region a net antibaryon density, both compensating each other such that the total baryon number is zero. For π−the effect is opposite., European H2020 MSCA-COFUND 754510,824093,H2020-INFRAIA-2018-1, Polish National Science Centre 2018/31/B/ST2/01022, Generalitat de Catalunya 2017SGR1069, Ministerio de Economía y Competitividad FPA2017-86989-P,SEV-2016-0588 MINECO, European Regional Development Fund FIS2017-85053-C2-1-P ERDF, Junta de Andalucía FQM-225

Chiral and pion superfluidity phase transitions are studied within NJL model. The model parameters are fitted by pion mass and decay constant together with recent isospin density from lattice QCD. Dense and cold QCD matter suffered the first order chiral phase transition during the quark chemical potential increase. Based on the studies of phase structures, the equation of states (EoS) of dense QCD matter is calculated with the conditions of β equilibrium and electric charge neutrality. Take the EoS as input, the mass-radius relation of up-down quark stars is predicted, which is consistent with recent observations of heaviest mass and radius of 1.4M⊙.

We show that the experimental data of transverse momentum ( p T ) spectra of identified hadrons released recently by ALICE collaboration for p–Pb collisions at s N N = 5.02 TeV exhibit a distinct universal behavior — the quark number scaling. We further show that the scaling is a direct consequence of quark (re-)combination mechanism of hadronization and can be regarded as a strong indication of the existence of the underlying source with constituent quark degree of freedom for the production of hadrons in p–Pb collisions at such high energies. We make also predictions for production of other hadrons.

While the constituent quark model (CQM), in which the quarks are assumed to be the complex objects, is used to calculate the parton distribution functions of the iso-scalar lithium-6 (6Li) nucleus, the u–d constituent quark distribution functions of the 6Li nucleus are evaluated from the valence quark exchange formalism (VQEF) for the A = 6 iso-scalar system. After computing the valence quark, sea quark, and gluon distribution functions in the constituent quark exchange model (CQEM, i.e., CQM + VQEF ), the nucleus structure function is calculated for the 6Li nucleus at the leading order (LO) and the next-to-leading-order (NLO) levels to extract the European muon collaboration (EMC) ratio, at different hard scales, using the standard Dokshitzer–Gribov–Lipatov–Altarelli–Parisi (DGALP) evolution equations. The outcomes are compared with those of our previous works and the available NMC experimental data, and various physical points are discussed. It is observed that the present EMC ratios are considerably improved compared with those of our previous works, in which only the valence quark distributions were considered to calculate the EMC ratio, and are closer to the NMC data. Finally, it is concluded that at a given appropriate hard scale, the LO approximation may be enough for calculating the nucleus EMC ratio.

The possible existence of stable up-down quark matter (udQM) was recently proposed, and it was shown that the properties of udQM stars are consistent with various pulsar observations. In this work we investigate the stability of udQM nuggets and found at certain size those objects are more stable than others if a large symmetry energy and a small surface tension were adopted. In such cases, a crust made of udQM nuggets exists in quark stars. A new family of white dwarfs comprised entirely of udQM nuggets and electrons were also obtained, where the maximum mass approaches to the Chandrasekhar limit.

As an improvement of the QCD sum rule method to study modifications of light vector mesons in nuclear matter and/or at finite temperature, we calculate the Wilson coefficients of all independent gluonic non-scalar operators up to dimension 6 in the operator product expansion (OPE) of the vector channel for light quarks. To obtain the gluon part of the light quark OPE from the heavy quark one, we also compute the heavy quark expansion of the relevant quark condensates. Together with the results for the quark operators that are already available in the literature, this completes the OPE of the vector channel in a hot or dense medium for operators up to dimension 6., 6 pages, no figure

We calculate the single-spin asymmetries A L W ± of W ± bosons produced in polarized pp collisions with the valence part of the up and down quark helicity distributions modeled by the light-cone quark-spectator–diquark model while the sea part helicity distributions of the up and down quarks treated as parametrization. Comparing our results with those from experimental data at RHIC, we find that the helicity distributions of sea quarks play an important role in the determination of the shapes of A L W ± . It is shown that A L W − is sensitive to Δ u ¯ , while A L W + to Δ d ¯ intuitively. The experimental data of the polarized structure functions and the sum of helicities are also important to constrain the sizes of quark helicity distributions both for the sea part and the valence part of the nucleon.

A radiative model of quark and lepton masses utilizing the binary tetrahedral ($T^{\prime}$) flavor symmetry, or horizontal symmetry, is proposed which produces the first two generation of quark masses through their interactions with vector-like quarks that carry charges under an additional $U(1)$. By softly-breaking the $T^{\prime}$ to a residual $Z_4$ through the vector-like quark masses, a CKM mixing angle close to the Cabibbo angle is produced. In order to generate the cobimaximal neutrino oscillation pattern ($\theta_{13}\neq0,\theta_{23}=\pi/4,\delta_{CP}=\pm \pi/2$) and protect the horizontal symmetry from arbitrary corrections in the lepton sector, there are automatically two stabilizing symmetries in the dark sector. Several benchmark cases where the correct relic density is achieved in a multi-component DM scenario, as well as the potential collider signatures of the vector-like quarks are discussed., Comment: 28 pages, 8 figures