Search results for "mass [leptoquark]"
showing 10 items of 519 documents
Flavor Symmetry and Vacuum Aligned Mass Textures
2006
21 pages, 2 figures.-- ArXiv pre-print available at: http://arxiv.org/abs/hep-ph/0609220
Neutrino Mass Ordering from Oscillations and Beyond: 2018 Status and Future Prospects
2018
The ordering of the neutrino masses is a crucial input for a deep understanding of flavor physics, and its determination may provide the key to establish the relationship among the lepton masses and mixings and their analogous properties in the quark sector. The extraction of the neutrino mass ordering is a data-driven field expected to evolve very rapidly in the next decade. In this review, we both analyze the present status and describe the physics of subsequent prospects. Firstly, the different current available tools to measure the neutrino mass ordering are described. Namely, reactor, long-baseline (accelerator and atmospheric) neutrino beams, laboratory searches for beta and neutrinol…
Few-body quark dynamics for doubly heavy baryons and tetraquarks
2018
We discuss the adequate treatment of the 3- and 4-body dynamics for the quark model picture of double-charm baryons and tetraquarks. We stress that the variational and Born-Oppenheimer approximations give energies very close to the exact ones, while the diquark approximation might be rather misleading. The Hall-Post inequalities also provide very useful lower bounds that exclude the possibility of stable tetraquarks for some mass ratios and some color wave functions.
Flavour and CP predictions from orbifold compactification
2020
We propose a theory for fermion masses and mixings in which an $A_4$ family symmetry arises naturally from a six-dimensional spacetime after orbifold compactification. The flavour symmetry leads to the successful "golden" quark-lepton unification formula. The model reproduces oscillation parameters with good precision, giving sharp predictions for the CP violating phases of quarks and leptons, in particular $\delta^\ell \simeq +268 ^\circ$. The effective neutrinoless double-beta decay mass parameter is also sharply predicted as $\langle m_{\beta\beta}\rangle \simeq 2.65\ meV$.
Determination of the light quark masses from eta -\rightarrow 3 pi
2012
Recently, several experimental collaborations have invested considerable effort into new and more precise measurements of the η ! 3π decays. These experimental advances require revisiting the corresponding theoretical analyses. In this work, we present a new calculation of the η ! 3π decay amplitude relying on dispersive methods. We show how the study of this decay allows one to extract a fundamental parameter of the Standard Model, namely the quark mass ratio Q 2 � (m 2 − ˆ m 2 )/(m 2 − m 2), with good precision. We find Q = 21.3� 0.6. We then discuss the
Consistency between SU(3) and SU(2) covariant baryon chiral perturbation theory for the nucleon mass
2017
Abstract Treating the strange quark mass as a heavy scale compared to the light quark mass, we perform a matching of the nucleon mass in the SU(3) sector to the two-flavor case in covariant baryon chiral perturbation theory. The validity of the 19 low-energy constants appearing in the octet baryon masses up to next-to-next-to-next-to-leading order [1] is supported by comparing the effective parameters (the combinations of the 19 couplings) with the corresponding low-energy constants in the SU(2) sector [2] . In addition, it is shown that the dependence of the effective parameters and the pion-nucleon sigma term on the strange quark mass is relatively weak around its physical value, thus pro…
Determination of m¯b/m¯c and m¯b from nf=4 lattice QCD+QED
2021
We extend HPQCD's earlier ${n}_{f}=2+1+1$ lattice-QCD analysis of the ratio of $\overline{\mathrm{MS}}$ masses of the $b$ and $c$ quark to include results from finer lattices (down to 0.03 fm) and a new calculation of QED contributions to the mass ratio. We find that ${\overline{m}}_{b}(\ensuremath{\mu})/{\overline{m}}_{c}(\ensuremath{\mu})=4.586(12)$ at renormalization scale $\ensuremath{\mu}=3\text{ }\text{ }\mathrm{GeV}$. This result is nonperturbative. Combining it with HPQCD's recent lattice $\mathrm{QCD}+\mathrm{QED}$ determination of ${\overline{m}}_{c}(3\text{ }\text{ }\mathrm{GeV})$ gives a new value for the $b$-quark mass: ${\overline{m}}_{b}(3\text{ }\text{ }\mathrm{GeV})=4.513(2…
First measurement of the charge asymmetry in beauty-quark pair production.
2014
The difference in the angular distributions between beauty quarks and antiquarks, referred to as the charge asymmetry, is measured for the first time in b[bar over b] pair production at a hadron collider. The data used correspond to an integrated luminosity of 1.0 fb[superscript −1] collected at 7 TeV center-of-mass energy in proton-proton collisions with the LHCb detector. The measurement is performed in three regions of the invariant mass of the b[bar over b] system. The results obtained are A[b[bar over b] over C](40 105 GeV/c[superscript 2]) = 1.6 ± 1.7 ± 0.6%, where A[b[bar over b] over C] is defined as the asymmetry in the difference in rapidity between jets formed from the beauty q…
Peak shape for a quadrupole mass spectrometer: comparison of computer simulation and experiment
2000
Abstract Computer simulations of ion trajectories have been used to evaluate the performance of a quadrupole mass spectrometer. Consideration has been given to realistic fields modeled on a commercial system as well as experimental distributions with respect to ion entry position, axial and radial velocity and relative phase of the quadrupole field. Determination of the mass filter acceptance-area as a function of the mass setting yields mass peak shapes with a dynamic range of more than seven orders of magnitude and thus provides estimates for abundance sensitivity. Results from these simulations are found to give excellent agreement with experimental measurements for different elements in…
Case Study of Potential Production of Renewable Energy Sources (RES) from Livestock Wastes in Mediterranean Islands
2017
The aim of this work is to evaluate the potential production of Renewable Energy Sources (RES) from livestock wastes that are commonly found on Mediterranean islands, by using the island of Malta as a case study. Organic wastes in the form of livestock manure and slurry, as well as other by-products originating from the food transformation industry in the making of alcoholic beverages and the processing of olives, tomatoes and other streams, if mixed in such a way to achieve a correct C/N ratio, can be subjected to anaerobic co-digestion for the production of biogas and digestate. Biogas can be further transformed into biomethane, a fuel that can be used to power surface transportation and …