Unified Charge Vectors (UCV) Theory

A grand unification of electroweak and strong forces is presented based on a new idea called Unified Charged Vectors. Using this new concept, it is shown that: The electroweak and strong forces can be unified into a single electro-weak-strong force. The various charges and coupling constants of fermions (like the electroweak mixing angle) can be predicted, rather than presupposed. The Lagrangian symmetries can be predicted rather than presupposed. The standard model Lagrangian can be cast into a simple unified form.

Precision electroweak measurements with the CMS detector

Recent results by the CMS experiment on Drell–Yan, W and multiboson events are presented, including in particular the measurement of the electroweak mixing angle, the differential distributions in Drell–Yan events, and the electroweak production of one and two vector bosons in association with two jets. No deviations from the Standard Model predictions are found and stringent bounds are set on anomalous triple and quartic gauge couplings.

Solar neutrino detection sensitivity in DARWIN via electron scattering

We detail the sensitivity of the proposed liquid xenon DARWIN observatory to solar neutrinos via elastic electron scattering. We find that DARWIN will have the potential to measure the fluxes of five solar neutrino components: pp, $$^7$$ 7 Be, $$^{13}$$ 13 N, $$^{15}$$ 15 O and pep. The precision of the $$^{13}$$ 13 N, $$^{15}$$ 15 O and pep components is hindered by the double-beta decay of $$^{136}$$ 136 Xe and, thus, would benefit from a depleted target. A high-statistics observation of pp neutrinos would allow us to infer the values of the electroweak mixing angle, $$\sin ^2\theta _w$$ sin 2 θ w , and the electron-type neutrino survival probability, $$P_{ee}$$ P ee , in the electron recoil energy region from a few keV up to 200 keV for the first time, with relative precision of 5% and 4%, respectively, with 10 live years of data and a 30 tonne fiducial volume. An observation of pp and $$^7$$ 7 Be neutrinos would constrain the neutrino-inferred solar luminosity down to 0.2%. A combination of all flux measurements would distinguish between the high- (GS98) and low-metallicity (AGS09) solar models with 2.1–2.5$$\sigma $$ σ significance, independent of external measurements from other experiments or a measurement of $$^8$$ 8 B neutrinos through coherent elastic neutrino-nucleus scattering in DARWIN. Finally, we demonstrate that with a depleted target DARWIN may be sensitive to the neutrino capture process of $$^{131}$$ 131 Xe.

Asymmetries in Processes of Electron–Positron Annihilation

Processes of electron–positron annihilation into a pair of fermions were considered. Forward–backward and left–right asymmetries were studied, taking into account polarization of initial and final particles. Complete 1-loop electroweak radiative corrections were included. A wide energy range including the Z boson peak and higher energies relevant for future e + e − colliders was covered. Sensitivity of observable asymmetries to the electroweak mixing angle and fermion weak coupling was discussed.

Using Machine Learning for Precision Measurements

The use of machine learning techniques for classification is well established. They are applied widely to improve the signal-to-noise ratio and the sensitivity of searches for new physics at colliders. In this study I explore the use of machine learning for optimizing the output of high precision experiments by selecting the most sensitive variables to the quantity being measured. The precise determination of the electroweak mixing angle at the Large Hadron Collider using linear or deep neural network regressors is developed as a test case.

Precision spectroscopy of trapped radioactive radium ions This paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at École de Physique, les Houches, France, 30 May – 4 June, 2010.

Atomic parity violation (APV) can be measured in a single Ra+ ion, enabling a precise measurement of the electroweak mixing angle in the Standard Model of particle physics at low momentum transfer. This provides sensitivity to new particles such as extra Z0 bosons or leptoquarks. The Weinberg angle can be measured via a determination of the light shift in the forbidden 72S1/2–62D3/2 transition in a single trapped Ra+. Ultra-narrow transitions in such an ideal system can also be exploited to realize a high stability frequency standard. At the TRIμP facility of KVI, we have succeeded in the production of a series of radioactive short-lived radium isotopes. The radium isotopes produced were stopped and thermalized to Ra+ in a thermal ionizer, mass separated in a Wien filter, cooled in a gas filled radio frequency quadrupole and subsequently trapped as a cloud in a linear Paul trap. Laser spectroscopy in the trapped radium ions has been performed. The results of hyperfine structure, isotope shift, and lifetime measurements are important experimental inputs to test the accuracy of atomic theory, the precision of which is indispensable for extracting the Weinberg angle. These results are also of relevance for a possible atomic clock, based on trapped Ra+.

Atomic parity violation in a single trapped radium ionThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at École de Physique, les Houches, France, 30 May – 4 June, 2010.

Atomic parity violation (APV) experiments are sensitive probes of the electroweak interaction at low energy. These experiments are competitive with and complementary to high-energy collider experiments. The APV signal is strongly enhanced in heavy atoms, and it is measurable by exciting suppressed (M1, E2) transitions. The predicted enhancement factor of the APV effect in the S-D transition in Ra+ is about 50 times larger than the S-S transition in neutral Cs. However, certain spectroscopic information on Ra+, needed to constrain the required atomic many-body theory, was lacking. Using the AGOR cyclotron and the TRIμP facility at KVI in Groningen, short-lived 212–214Ra+ ions were produced and trapped. First ever excited-state laser spectroscopy was performed on the trapped ions. These measurements provide a benchmark for the atomic theory required to extract the electroweak mixing angle to sub 1% accuracy and are an important step towards an APV experiment in a single trapped Ra+ ion. A lower bound on the radiative lifetime of the 62D5/2 state was found of 232(4) ms. This experimental confirmation of the long coherence time of the meta-stable 62D5/2 state is important in light of the possibility of using a single trapped radium ion as an optical frequency standard.