scholarly journals $$U(1)_{B_3-L_2}$$ explanation of the neutral current $$B-$$anomalies

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
B. C. Allanach
Keyword(s):  
Standard Model ◽  
Neutral Current ◽  
Vector Boson ◽  
Baryon Number ◽  
Higgs Bosons ◽  
Complex Scalar ◽  
Quantum Numbers ◽  
The Standard Model ◽  
Model Predictions ◽  
Rule Out

AbstractWe investigate a speculative short-distance force, proposed to explain discrepancies observed between measurements of certain neutral current decays of B hadrons and their Standard Model predictions. The force derives from a spontaneously broken, gauged $$U(1)_{B_3-L_2}$$ U ( 1 ) B 3 - L 2 extension to the Standard Model, where the extra quantum numbers of Standard Model fields are given by third family baryon number minus second family lepton number. The only fields beyond those of the Standard Model are three right-handed neutrinos, a gauge field associated with $$U(1)_{B_3-L_2}$$ U ( 1 ) B 3 - L 2 and a Standard Model singlet complex scalar which breaks $$U(1)_{B_3-L_2}$$ U ( 1 ) B 3 - L 2 , a ‘flavon’. This simple model, via interactions involving a TeV scale force-carrying $$Z^\prime $$ Z ′ vector boson, can successfully explain the neutral current $$B-$$ B - anomalies whilst accommodating other empirical constraints. In an ansatz for fermion mixing, a combination of up-to-date $$B-$$ B - anomaly fits, LHC direct $$Z^\prime $$ Z ′ search limits and other bounds rule out the domain 0.15 $$\hbox {TeV}< M_{Z^\prime }<$$ TeV < M Z ′ < 1.9 TeV at the $$95\%$$ 95 % confidence level. For more massive $$Z^\prime $$ Z ′ s, the model possesses a flavonstrahlung signal, where pp collisions produce a $$Z^\prime $$ Z ′ and a flavon, which subsequently decays into two Higgs bosons.

scholarly journals Dark moments for the Standard Model?

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Thomas G. Rizzo
Keyword(s):  
Standard Model ◽  
Magnetic Dipole ◽  
Parameter Space ◽  
Gauge Coupling ◽  
Large Mass ◽  
Mass Scale ◽  
Complex Scalar ◽  
Quantum Numbers ◽  
The Standard Model ◽  
Model Setup

Abstract If dark matter (DM) interacts with the Standard Model (SM) via the kinetic mixing (KM) portal, it necessitates the existence of portal matter (PM) particles which carry both dark and SM quantum numbers that will appear in vacuum polarization-like loop graphs. In addition to the familiar ∼ eϵQ strength, QED-like interaction for the dark photon (DP), in some setups different loop graphs of these PM states can also induce other coupling structures for the SM fermions that may come to dominate in at least some regions of parameter space regions and which can take the form of ‘dark’ moments, e.g., magnetic dipole-type interactions in the IR, associated with a large mass scale, Λ. In this paper, motivated by a simple toy model, we perform a phenomenological investigation of a possible loop-induced dark magnetic dipole moment for SM fermions, in particular, for the electron. We show that at the phenomenological level such a scenario can not only be made compatible with existing experimental constraints for a significant range of correlated values for Λ and the dark U(1)D gauge coupling, gD, but can also lead to quantitatively different signatures once the DP is discovered. In this setup, assuming complex scalar DM to satisfy CMB constraints, parameter space regions where the DP decays invisibly are found to be somewhat preferred if PM mass limits from direct searches at the LHC and our toy model setup are all taken seriously. High precision searches for, or measurements of, the e+e− → γ + DP process at Belle II are shown to provide some of the strongest future constraints on this scenario.

scholarly journals Exploration of Extended Higgs Sectors with Run-2 Proton–Proton Collision Data at the LHC

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2144
Author(s):  
Arnaud Ferrari ◽  
Nikolaos Rompotis
Keyword(s):  
Standard Model ◽  
Higgs Sector ◽  
Scalar Fields ◽  
Higgs Bosons ◽  
Proton Collision ◽  
Complex Scalar ◽  
Proton Proton ◽  
The Standard Model ◽  
Extended Higgs Sectors ◽  
Proton Proton Collision

One doublet of complex scalar fields is the minimal content of the Higgs sector in order to achieve spontaneous electroweak symmetry breaking and, in turn, to generate the masses of fundamental particles in the Standard Model. However, several theories beyond the Standard Model predict a nonminimal Higgs sector and introduce additional singlets, doublets or even higher-order weak isospin representations, thereby yielding additional Higgs bosons. With its high proton–proton collision energy (13 TeV during Run-2), the Large Hadron Collider opens a new window towards the exploration of extended Higgs sectors. This review article summarises the current state-of-the-art experimental results recently obtained in searches for new neutral and charged Higgs bosons with a partial or full Run-2 dataset.

scholarly journals Precision SMEFT bounds from the VBF Higgs at high transverse momentum

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Jack Y. Araz ◽  
Shankha Banerjee ◽  
Rick S. Gupta ◽  
Michael Spannowsky
Keyword(s):  
Standard Model ◽  
Vector Boson ◽  
High Energy ◽  
Effective Field ◽  
Higgs Bosons ◽  
Quadratic Growth ◽  
Final States ◽  
High Transverse Momentum ◽  
The Standard Model ◽  
Independent Operator

Abstract We study the production of Higgs bosons at high transverse momenta via vector-boson fusion (VBF) in the Standard Model Effective Field Theory (SMEFT). We find that contributions from four independent operator combinations dominate in this limit. These are the same ‘high energy primaries’ that control high energy diboson processes, including Higgs-strahlung. We perform detailed collider simulations for the diphoton decay mode of the Higgs boson as well as the three final states arising from the ditau channel. Using the quadratic growth of the SMEFT contributions relative to the Standard Model (SM) contribution, we project very stringent bounds on these operators that far surpass the corresponding bounds from the LEP experiment.

VECTOR BOSON DOMINANCE OF ELECTROWEAK INTERACTIONS

1993 ◽  
Vol 08 (33) ◽  
pp. 3129-3138 ◽  
Author(s):  
YU. F. PIROGOV
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Vector Boson ◽  
Local Symmetry ◽  
Higgs Bosons ◽  
Quantum Field ◽  
Gauge Bosons ◽  
The Standard Model ◽  
Vector Bosons ◽  
Common Substructure

The linearization of the nonlinear standard model G/H= SU(3) L × U(1)/SU(2) L × U(1) via the hidden local symmetry H loc = SU(2) L × U(1) is considered. Mixing of the light elementary gauge bosons of the standard model with the dynamically generated heavy composite vector bosons is studied under the hypothesis of vector boson dominance. The model is theoretically consistent as quantum field theory and phenomenologically acceptable. It can be used as a guide to study systematically the deviations from the standard model due to a common substructure of leptons, quarks and Higgs bosons.

CDF Run II Prospects for Bs Mixing

2001 ◽  
Vol 16 (supp01a) ◽  
pp. 419-421
Author(s):  
Matthew S. Martin
Keyword(s):  
Standard Model ◽  
The Standard Model ◽  
Model Predictions ◽  
Cdf Run Ii ◽  
Rule Out

We give a prediction of the Bs mixing reach (xs) for the first two years of CDF Run II. We mention the important samples, and their expected yields. If the experiment performs to our expectations, we expect either to measure Bs mixing, or to comprehensively rule out the Standard Model predictions.

scholarly journals High $$P_T$$ Higgs excess as a signal of non-local QFT at the LHC

2021 ◽  
Vol 81 (9) ◽  
Author(s):  
Xing-Fu Su ◽  
You-Ying Li ◽  
Rosy Nicolaidou ◽  
Min Chen ◽  
Hsin-Yeh Wu ◽  
...  
Keyword(s):  
Standard Model ◽  
Cross Sections ◽  
Higgs Mass ◽  
Vector Boson ◽  
Higgs Bosons ◽  
Enhanced Production ◽  
The Standard Model ◽  
Non Local ◽  
Infinite Derivative ◽  
Non Locality

AbstractNon-local extensions of the Standard Model with a non-locality scale $$\varLambda _{NL}$$ Λ NL have the effect of smearing the pointlike vertices of the Standard Model. At energies significantly lower than $$\varLambda _{NL}$$ Λ NL vertices appear pointlike, while beyond this scale all beta functions vanish and all couplings approach a fixed point leading to scale invariance. Non-local SM extensions are ghost free, with the non-locality scale serving as an effective cutoff to radiative corrections of the Higgs mass. We argue that the data expected to be collected at the LHC phase 2 will have a sensitivity to non-local effects originating from a non-locality scale of a few TeV. Using an infinite derivative prescription, we study modifications to heavy vector-boson cross sections that can lead to an enhanced production of boosted Higgs bosons in a region of the kinematic phase space where the SM background is very small.

scholarly journals B decay anomalies at LHCb

2018 ◽  
Vol 175 ◽  
pp. 01004
Author(s):  
Arantza Oyanguren
Keyword(s):  
Standard Model ◽  
B Meson ◽  
Neutral Current ◽  
New Physics ◽  
Lhcb Collaboration ◽  
Beyond The Standard Model ◽  
Clear Tendency ◽  
The Standard Model ◽  
Model Predictions ◽  
Lepton Flavour

The LHCb collaboration has provided a plethora of precise measurements of flavour observables in the last years. In the B meson sector some of these results show consistent deviations from Standard Model predictions with a clear tendency to specific New Physics scenarios. B decay anomalies are found in particular related to lepton flavour universality tests and angular observables in Flavour-Changing-Neutral-Current transitions. I review here the LHCb measurements and their experimental caveats. Results from Lattice are crucial in the coming years to verify if these anomalies are explained by QCD effects or if they are unambiguous hints of physics beyond the Standard Model.

scholarly journals PREDICTED SIGNATURES AT THE LHC FROM U(1) EXTENSIONS OF THE STANDARD MODEL

2010 ◽  
Vol 25 (36) ◽  
pp. 3003-3016 ◽  
Author(s):  
PRAN NATH
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Vector Boson ◽  
Hadron Collider ◽  
Mass Growth ◽  
Hidden Sector ◽  
Quantum Numbers ◽  
The Standard Model ◽  
Vector Bosons

We discuss the U (1)X extensions of the standard model with focus on the Stueckelberg mechanism for mass growth for the extra U (1)X gauge boson. The assumption of an axionic connector field which carries dual U(1) quantum numbers, i.e. quantum numbers for the hypercharge U(1) Y and for the hidden sector gauge group U (1)X, allows a nontrivial mixing between the mass growth for the neutral gauge vector bosons in the SU(2) L × U (1)Y sector and the mass growth for the vector boson by the Stueckelberg mechanism in the U (1)X sector. This results in an extra Z′ which can be very narrow, but still detectable at the Large Hadron Collider (LHC). The U (1)X extension of the minimal supersymmetric standard model is also considered and the role of the Fayet–Illiopoulos term in such an extension discussed. The U (1)X extensions of the SM and of the MSSM lead to new candidates for dark matter.

scholarly journals Naturalising the third family hypercharge model for neutral current $$B{-}\hbox {anomalies}$$

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
B. C. Allanach ◽  
Joe Davighi
Keyword(s):  
Gauge Symmetry ◽  
Standard Model ◽  
Neutral Current ◽  
Beyond The Standard Model ◽  
Yukawa Couplings ◽  
The Third ◽  
Standard Model Contribution ◽  
The Standard Model ◽  
Model Predictions ◽  
Flavour Violation

Abstract We consider a deformation of the Third Family Hypercharge Model, which arguably makes the model more natural. Additional non-zero charges of the spontaneously broken, family-dependent $$U(1)_F$$U(1)F gauge symmetry are assigned to the second family leptons, and the third family leptons’ charges are deformed away from their hypercharges in such a way that the $$U(1)_F$$U(1)F gauge symmetry remains anomaly-free. Second family $$U(1)_F$$U(1)F lepton charges allow a $$Z^\prime $$Z′ coupling to muons without having to assume large charged lepton mixing, which risks violating tight lepton flavour violation bounds. In this deformed version, only the bottom and top Yukawa couplings are generated at the renormalisable level, whereas the tauon Yukawa coupling is absent. The $$Z^\prime $$Z′ mediates a beyond the Standard Model contribution to an effective $$({\bar{b}} s) (\bar{\mu }\mu )$$(b¯s)(μ¯μ) vertex in the combination $$C_9=-9C_{10}$$C9=-9C10 and is able to fit the apparent discrepancy between Standard Model predictions in flavour changing neutral-current $$B-$$B-meson decays and their measurements, whilst simultaneously avoiding current constraints from direct $$Z^\prime $$Z′ searches and other measurements, when $$0.8~\text {TeV}< M_{Z^\prime } < 12.5 ~\text {TeV}$$0.8TeV<MZ′<12.5TeV.

scholarly journals Measurements of Higgs bosons decaying to bottom quarks from vector boson fusion production with the ATLAS experiment at $$\sqrt{s}=13\,\text {TeV}$$

2021 ◽  
Vol 81 (6) ◽  
Author(s):  
◽  
G. Aad ◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Standard Model ◽  
Vector Boson ◽  
Hadron Collider ◽  
Higgs Bosons ◽  
Measured Signal ◽  
Proton Collision ◽  
Vector Boson Fusion ◽  
Quark Pairs ◽  
Atlas Experiment ◽  
The Standard Model

AbstractThe paper presents a measurement of the Standard Model Higgs Boson decaying to b-quark pairs in the vector boson fusion (VBF) production mode. A sample corresponding to 126 $$\hbox {fb}^{-1}$$ fb - 1 of $$\sqrt{s} = 13\,\text {TeV}$$ s = 13 TeV proton–proton collision data, collected with the ATLAS experiment at the Large Hadron Collider, is analyzed utilizing an adversarial neural network for event classification. The signal strength, defined as the ratio of the measured signal yield to that predicted by the Standard Model for VBF Higgs production, is measured to be $$0.95^{+0.38}_{-0.36}$$ 0 . 95 - 0.36 + 0.38 , corresponding to an observed (expected) significance of 2.6 (2.8) standard deviations from the background only hypothesis. The results are additionally combined with an analysis of Higgs bosons decaying to b-quarks, produced via VBF in association with a photon.

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