| 1. |
- Ben-Shahar, Maor, et al.
(author)
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10D super-Yang-Mills scattering amplitudes from its pure spinor action
- 2021
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In: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :12
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Journal article (peer-reviewed)abstract
- Using the pure spinor master action for 10D super-Yang-Mills in the gauge b0V = QΞ, tree-level scattering amplitudes are calculated through the perturbiner method, and shown to match those obtained from pure spinor CFT techniques. We find kinematic numerators made of nested b-ghost operators, and show that the Siegel gauge condition b0V = 0 gives rise to color-kinematics duality satisfying numerators whose Jacobi identity follows from the Jacobi identity of a kinematic algebra.
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| 2. |
- Ben-Shahar, Maor, et al.
(author)
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Superspace expansion of the 11D linearized superfields in the pure spinor formalism, and the covariant vertex operator
- 2023
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In: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :9
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Journal article (peer-reviewed)abstract
- 11D pure spinors have been shown to successfully describe 11D supergravity in a manifestly super-Poincare covariant manner. The feasibility of its actual usage for scattering amplitude computations requires an efficient manipulation of the superfields defining linearized 11D supergravity. In this paper, we directly address this problem by finding the superspace expansions of these superfields, at all orders in., from recursive relations their equations of motion obey in Harnad-Shnider-like gauges. After introducing the 11D analogue of the 10D ABC superparticle, we construct, for the first time, a fully covariant vertex operator for 11D supergravity by making use of the linearized 11D superfields. Notably, we show that this vertex reproduces the Green-Gutperle-Kwon 11D operators in light-cone gauge.
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| 3. |
- Chargari, Cyrus, et al.
(author)
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Brachytherapy for Pediatric Patients at Gustave Roussy Cancer Campus : A Model of International Cooperation for Highly Specialized Treatments
- 2022
-
In: International Journal of Radiation Oncology Biology Physics. - : Elsevier BV. - 0360-3016. ; 113:3, s. 602-613
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Journal article (peer-reviewed)abstract
- Purpose: Childhood cancer is rare, and treatment is frequently associated with long-term morbidity. Disparities in survival and long-term side effects encourage the establishment of networks to increase access to complex organ-conservative strategies, such as brachytherapy. We report our experience of an international cooperation model in childhood cancers. Methods and Materials: We examined the outcome of all children referred to our center from national or international networks to be treated according to a multimodal organ-conservative approach, including brachytherapy. Results: We identified 305 patients whose median age at diagnosis was 2.2 years (range, 1.4 months to 17.2 years). Among these patients, 99 (32.4%) were treated between 2015 and 2020; 172 (56.4%) were referred from national centers; and 133 (43.6%) were international patients from 31 countries (mainly Europe). Also, 263 patients were referred for primary treatment and 42 patients were referred for salvage treatment. Genitourinary tumors were the most frequent sites, with 56.4% bladder/prostate rhabdomyosarcoma and 28.5% gynecologic tumors. In addition to brachytherapy, local treatment consisted of partial tumor resection in 207 patients (67.9%), and 39 patients (13%) had additional external radiation therapy. Median follow-up was 58 months (range, 1 month to 48 years), 93 months for national patients, and 37 months for international patients (P < .0001). Five-year local control, disease-free survival, and overall survival rates were 90.8% (95% confidence interval [CI], 87.3%-94.4%), 84.4% (95% CI, 80.1%-89.0%), and 93.3% (95% CI, 90.1%-96.5%), respectively. Patients referred for salvage treatment had poorer disease-free survival (P < .01). Implementation of image guided pulse-dose-rate brachytherapy was associated with better local control among patients with rhabdomyosarcoma referred for primary treatment (hazard ratio, 9.72; 95% CI, 1.24-71.0). At last follow-up, 16.7% patients had long-term severe treatment-related complications, and 2 patients (0.7%) had developed second malignancy. Conclusions: This retrospective series shows the feasibility of a multinational referral network for brachytherapy allowing high patient numbers in rare pediatric cancers. High local control probability and acceptable late severe complication probability could be achieved despite very challenging situations. This cooperation model could serve as a basis for generating international reference networks for high-tech radiation such as brachytherapy to increase treatment care opportunities and cure probability.
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| 4. |
- Edison, Alex, et al.
(author)
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One-loop matrix elements of effective superstring interactions : α'-expanding loop integrands
- 2021
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In: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :12
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Journal article (peer-reviewed)abstract
- In the low-energy effective action of string theories, non-abelian gauge interactions and supergravity are augmented by infinite towers of higher-mass-dimension operators. We propose a new method to construct one-loop matrix elements with insertions of operators D2k Fn and D2k Rn in the tree-level effective action of type-I and type-II superstrings. Inspired by ambitwistor string theories, our method is based on forward limits of moduli-space integrals using string tree-level amplitudes with two extra points, expanded in powers of the inverse string tension α′. Similar to one-loop ambitwistor computations, intermediate steps feature non-standard linearized Feynman propagators which eventually recombine to conventional quadratic propagators. With linearized propagators the loop integrand of the matrix elements obey one-loop versions of the monodromy and KLT relations. We express a variety of four- and five-point examples in terms of quadratic propagators and formulate a criterion on the underlying genus-one correlation functions that should make this recombination possible at all orders in α′. The ultraviolet divergences of the one-loop matrix elements are crosschecked against the non-separating degeneration of genus-one integrals in string amplitudes. Conversely, our results can be used as a constructive method to determine degenerations of elliptic multiple zeta values and modular graph forms at arbitrary weight.
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| 5. |
- Edison, Alex, et al.
(author)
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One-loop matrix elements of effective superstring interactions : alpha '-expanding loop integrands
- 2021
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In: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :12
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Journal article (peer-reviewed)abstract
- In the low-energy effective action of string theories, non-abelian gauge interactions and supergravity are augmented by infinite towers of higher-mass-dimension operators. We propose a new method to construct one-loop matrix elements with insertions of operators (DFn)-F-2k and (DRn)-R-2k in the tree-level effective action of type-I and type-II superstrings. Inspired by ambitwistor string theories, our method is based on forward limits of moduli-space integrals using string tree-level amplitudes with two extra points, expanded in powers of the inverse string tension alpha'. Similar to one-loop ambitwistor computations, intermediate steps feature non-standard linearized Feynman propagators which eventually recombine to conventional quadratic propagators. With linearized propagators the loop integrand of the matrix elements obey one-loop versions of the monodromy and KLT relations. We express a variety of four- and five-point examples in terms of quadratic propagators and formulate a criterion on the underlying genus-one correlation functions that should make this recombination possible at all orders in alpha'. The ultraviolet divergences of the one-loop matrix elements are crosschecked against the non-separating degeneration of genus-one integrals in string amplitudes. Conversely, our results can be used as a constructive method to determine degenerations of elliptic multiple zeta values and modular graph forms at arbitrary weight.
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| 6. |
- Guillen, Max
(author)
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Green-Schwarz and pure spinor formulations of chiral strings
- 2021
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In: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :12
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Journal article (peer-reviewed)abstract
- Bosonic and RNS chiral strings have been defined from a singular gauge fixing of the respective Polyakov and spinning string actions, enforcing, among other things, the finite nature of their physical spectra. Except for the heterotic case, the tensionless limits of such chiral models have been shown to describe the same field theories predicted by their ambitwistor analogues. In this paper, we study the Green-Schwarz formulation for Type II and heterotic superstrings in a singular gauge. After performing a light-cone gauge analysis, their physical spectra are shown to match those of RNS chiral strings, and their respective tensionless limits are found to describe the same field theories predicted by RNS ambitwistor strings. Their pure spinor counterparts are then introduced by making use of the Oda-Tonin method. In doing so, symmetries hidden in the pure spinor ambitwistor string action become manifest, proposals motivating the sectorized pure spinor BRST charges find simple grounds, and integrated vertex operators emerge naturally.
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| 7. |
- Guillen, Max
(author)
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Notes on the 11D pure spinor wordline vertex operators
- 2020
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In: Journal of High Energy Physics (JHEP). - : SPRINGER. - 1126-6708 .- 1029-8479. ; :8
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Journal article (peer-reviewed)abstract
- The construction of the ghost number zero and one vertex operators for the 11D pure spinor superparticle will be revisited. In this sense, an alternative way of defining the ghost number one vertex operator will be given after introducing a ghost number -2 operator made out of physical operators defined on the 11D non-minimal pure spinor superspace. This procedure will make explicit and transparent the relation between the ghost number three and one vertex operators. In addition, using a non-Lorentz covariant b-ghost, ghost number zero and two vertex operators satisfying standard descent equations will be presented in full form.
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| 8. |
- Guillen, Max, et al.
(author)
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Scattering Massive String Resonances through Field-Theory Methods
- 2021
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In: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 127:5
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Journal article (peer-reviewed)abstract
- We present a new method, exact in α′, to explicitly compute string tree-level amplitudes involving one massive state and any number of massless ones. This construction relies on the so-called twisted heterotic string, which admits only gauge multiplets, a gravitational multiplet, and a single massive supermultiplet in its spectrum. In this simplified model, we determine the moduli-space integrand of all amplitudes with one massive state using Berends-Giele currents of the gauge multiplet. These integrands are then straightforwardly mapped to gravitational amplitudes in the twisted heterotic string and to the corresponding massive amplitudes of the conventional type-I and type-II superstrings.
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| 9. |
- Guillen, Max
(author)
-
Taming the 11D pure spinor b-ghost
- 2023
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In: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479.
-
Journal article (peer-reviewed)abstract
- We provide an alternative compact expression for the 11D pure spinor b-ghost by introducing a new set of negative ghost number operators made out of non-minimal pure spinor variables. Using the algebraic properties satisfied by these operators, it will be straightforwardly shown that {Q, b} = P-2/2, as well as {b, b} = Q Omega. As an application of this novel formulation, the ghost number two vertex operator will easily be obtained in a completely covariant manner from a standard descent relation, the ghost number three vertex operator will be shown to satisfy the generalized Siegel gauge condition, and the 11D supergravity two-particle superfield will be constructed in a quite simple way.
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| 10. |
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| 11. |
- Sepulveda, Diego Garcia, et al.
(author)
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A pure spinor twistor description of the D=10 superparticle
- 2020
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In: Journal of High Energy Physics (JHEP). - : SPRINGER. - 1126-6708 .- 1029-8479. ; :8
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Journal article (peer-reviewed)abstract
- We present a novel twistor formulation of the ten-dimensional massless super-particle. This formulation is based on the introduction of pure spinor variables through a field redefinition of another model for the superparticle, and in the new description we find that the super-Pauli-Lubanski three-form naturally arises as a constraint. Quantization is studied in detail for both models and they are shown to correctly describe the D = 10 super-Yang-Mills states.
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