Disambiguating seesaw models using invariant mass variables at hadron colliders

Dev, P. S. Bhupal; Kim, Doojin; Mohapatra, Rabindra N.

doi:10.1007/jhep01(2016)118

Cited by 55 publications

(33 citation statements)

References 224 publications

(382 reference statements)

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“…Nevertheless, even for this last case of pair-production of semi-invisibly decaying particles, several methods for mass measurement have been developed, such as i) using kinematic endpoints of visible particle invariant mass distributions [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], which works only for two or more visible particles in the decay chain (thus necessarily facing combinatorics due to the pair-production), ii) the M T 2 variable 4 and its generalizations and variants , which often use MET, iii) polynomial methods [49][50][51][52][53], which often assume a specific event topology and impose an adequate number of on-shell constraints, or iv) the razor and related variables [54,55], which often need some assumptions about boosts of the mother particles. See also references [56][57][58][59][60][62][63][64][65][66] for other kinematic methods for mass measurement,…”

Section: Jhep04(2016)151mentioning

confidence: 99%

“…The massless limit of these expressions is given by the limit γ * d → ∞ and reads 16) as necessary to reproduce the massless result of (2.7). We emphasize that the addition of θ(γ kin − γ M ) enables us to easily keep track of the consequence of γ cr M being larger or smaller than θ(γ kin − γ M ) on the shape of the energy distribution.…”

Section: Jhep04(2016)151mentioning

confidence: 99%

“…According to this spirit we impose rather mild requirements on single objects used in our analysis: 16) in every single event that we use for our data analysis. Furthermore we remark that our signal tends to have multiple hard particles that are collectively giving a large recoil to the system of invisible particles.…”

Section: Jhep04(2016)151mentioning

confidence: 99%

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Energy spectra of massive two-body decay products and mass measurement

Agashe

Franceschini

Hong

et al. 2016

J. High Energ. Phys.

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Abstract:We have recently established a new method for measuring the mass of unstable particles produced at hadron colliders based on the analysis of the energy distribution of a massless product from their two-body decays. The central ingredient of our proposal is the remarkable result that, for an unpolarized decaying particle, the location of the peak in the energy distribution of the observed decay product is identical to the (fixed) value of the energy that this particle would have in the rest-frame of the decaying particle, which, in turn, is a simple function of the involved masses. In addition, we utilized the property that this energy distribution is symmetric around the location of peak when energy is plotted on a logarithmic scale. The general strategy was demonstrated in several specific cases, including both beyond the standard model particles, as well as for the top quark. In the present work, we generalize this method to the case of a massive decay product from a two-body decay; this procedure is far from trivial because (in general) both the abovementioned properties are no longer valid. Nonetheless, we propose a suitably modified parametrization of the energy distribution that was used successfully for the massless case, which can deal with the massive case as well. We test this parametrization on concrete examples of energy spectra of Z bosons from the decay of a heavier supersymmetric partner of top quark (stop) into a Z boson and a lighter stop. After establishing the accuracy of this parametrization, we study a realistic application for the same process, but now including dominant backgrounds and using foreseeable statistics at LHC14, in order to determine the performance of this method for an actual mass measurement. The upshot of our present and previous work is that, in spite of energy being a Lorentz-variant quantity, its distribution emerges as a powerful tool for mass measurement at hadron colliders.

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Section: Jhep04(2016)151mentioning

confidence: 99%

Section: Jhep04(2016)151mentioning

confidence: 99%

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Energy spectra of massive two-body decay products and mass measurement

Agashe

Franceschini

Hong

et al. 2016

J. High Energ. Phys.

Self Cite

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“…LR models provide also interesting candidates for a Z ′ boson as currently hinted at by b → sℓℓ observables [12][13][14]. Stringent constraints come from electroweak precision observables [15] and from direct searches at LHC [16][17][18][19][20], pushing the limit for LR models to several TeV. Studies in the framework of flavour physics suggest also that the structure for the right-handed CKM-like matrix should be quite different from the left-handed one, far from the manifest or pseudo-manifest scenarios [21][22][23][24][25].…”

Section: Jhep08(2016)128mentioning

confidence: 99%

Short-distance QCD corrections to K 0 K ¯ 0 $$ {K}^0{\overline{K}}^0 $$ mixing at next-to-leading order in Left-Right models

Bernard

Descotes-Genon

Silva

2016

J. High Energ. Phys.

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Left-Right (LR) models are extensions of the Standard Model where leftright symmetry is restored at high energies, and which are strongly constrained by kaon mixing described in the framework of the |∆S| = 2 effective Hamiltonian. We consider the short-distance QCD corrections to this Hamiltonian both in the Standard Model (SM) and in LR models. The leading logarithms occurring in these short-distance corrections can be resummed within a rigourous Effective Field Theory (EFT) approach integrating out heavy degrees of freedom progressively, or using an approximate simpler method of regions identifying the ranges of loop momentum generating large logarithms in the relevant twoloop diagrams. We compare the two approaches in the SM at next-to-leading order, finding a very good agreement when one scale dominates the problem, but only a fair agreement in the presence of a large logarithm at leading order. We compute the short-distance QCD corrections for LR models at next-to-leading order using the method of regions, and we compare the results with the EFT approach for the W W ′ box with two charm quarks (together with additional diagrams forming a gauge-invariant combination), where a large logarithm occurs already at leading order. We conclude by providing next-to-leading-order estimates for cc, ct and tt boxes in LR models.

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“…Additionally, the see-saw mechanism comes in rather naturally in the context of left-right symmetric scenarios; aside from other nice features, as for instance the recovery of parity symmetry, and the appearance of right-handed currents at high energy, which also makes such extensions very appealing. Recently, the left-right scenarios have been revised [15][16][17][18][19][20][21][22][23][24][25] in order to make contact with the latest experimental data of LHC. Moreover, the dark matter problem [26][27][28] and the diphoton excess anomaly [29][30][31][32][33] have been explored in this kind of scenarios.…”

Section: Introductionmentioning

confidence: 99%

Non-minimal flavored $${S}_{3}\otimes {Z}_{2}$$ S 3 ⊗ Z 2 left–right symmetric model

Gómez-Izquierdo

2017

Eur. Phys. J. C

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We propose a non-minimal left-right symmetric model with parity symmetry where the fermion mixings arise as a result of imposing an S 3 ⊗ Z 2 flavor symmetry, and an extra Z e 2 symmetry is considered in the lepton sector. Then the neutrino mass matrix possesses approximately the μ-τ symmetry. The breaking of the μ-τ symmetry induces sizable non-zero θ 13 , and the deviation of θ 23 from 45 • is strongly controlled by an free parameter and the neutrino masses. So, an analytic study of the CP parities in the neutrino masses is carried out to constrain the parameter and the lightest neutrino mass that accommodate the mixing angles. The results are: (a) the normal hierarchy is ruled out for any values of the Majorana phases; (b) for the inverted hierarchy the values of the reactor and atmospheric angles are compatible up to 2, 3 σ C.L.; (c) the degenerate ordering is the most favorable such that the reactor and atmospheric angle are compatible with the experimental data for a large set of values of the free parameters. The model predicts defined regions for the effective neutrino mass, the neutrino mass scale and the sum of the neutrino masses for the favored cases. Therefore, this model may be testable by the future experiments.

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Disambiguating seesaw models using invariant mass variables at hadron colliders

Cited by 55 publications

References 224 publications

Energy spectra of massive two-body decay products and mass measurement

Energy spectra of massive two-body decay products and mass measurement

Short-distance QCD corrections to K 0 K ¯ 0 $$ {K}^0{\overline{K}}^0 $$ mixing at next-to-leading order in Left-Right models

Non-minimal flavored $${S}_{3}\otimes {Z}_{2}$$ S 3 ⊗ Z 2 left–right symmetric model

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