Supersymmetric Model with Grassmann-odd Lagrangian

A supersymmetric $D = 1, N =1$ model with a Grassmann-odd Lagrangian is proposed which, in contrast to the model with an even Lagrangian, contains not only a kinetic term but also an interaction term for the coordinates entering into one real scalar Grassmann-even (bosonic) superfield.Comment: 6 pages, LATEX 2e. The talk given at the International Conference "Supersymmetries and Quantum Field Theory" (SSQFT'2000, NSC KIPT, Kharkov, Ukraine, 25-29 July, 2000). To be published in the Proceedings of this Conference. Corrections of misprint

Relativistic particle dynamics in D=2+1

We propose a SUSY variant of the action for a massless spinning particles via the inclusion of twistor variables. The action is constructed to be invariant under SUSY transformations and $\tau$-reparametrizations even when an interaction field is including. The constraint analysis is achieved and the equations of motion are derived. The commutation relations obtained for the commuting spinor variables $\lambda$ show that the particle states have fractional statistics and spin. At once we introduce a possible massive term for the non-interacting model.Comment: 11 page

Stringy Sphalerons and Non-Abelian Black Holes

Static spherically symmetric asymptotically flat particle-like and black hole solutions are constructed within the SU(2) sector of 4-dimensional heterotic string effective action. They separate topologically distinct Yang-Mills vacua and are qualitatively similar to the Einstein-Yang-Mills spha- lerons and non-abelian black holes discussed recently. New solutions possess quantized values of the dilaton charge.Comment: 12 pages, LATEX, (8 figures upon request

Higgsinoless Supersymmetry and Hidden Gravity

We present a simple formulation of non-linear supersymmetry where superfields and partnerless fields can coexist. Using this formalism, we propose a supersymmetric Standard Model without the Higgsino as an effective model for the TeV-scale supersymmetry breaking scenario. We also consider an application of the Hidden Local Symmetry in non-linear supersymmetry, where we can naturally incorporate a spin-two resonance into the theory in a manifestly supersymmetric way. Possible signatures at the LHC experiments are discussed.Comment: 30 pages, 3 figures, references added, version to appear in JHE

On the equivalence between real and superfield 5d formalisms

We explicitly prove the equivalence and construct a dictionary between two different supersymmetric formalisms for five-dimensional theories commonly used in the literature. One is the real formalism, which consists in doubling the number of degrees of freedom and then imposing reality constraints and the other is the usual superfield formalism.Comment: 19 page

Solitons and black holes in non-Abelian Einstein-Born-Infeld theory

Recently it was shown that the Born-Infeld-type modification of the quadratic Yang-Mills action gives rise to classical particle-like solutions in the flat space which have a striking similarity with the Bartnik-McKinnon solutions known in the gravity coupled Yang-Mills theory. We show that both families are continuously related within the framework of the Einstein-Born-Infeld theory through interpolating sequences of parameters. We also investigate an internal structure of the associated black holes. It is found that the Born-Infeld non-linearity leads to a drastic modification of the black hole interior typical for the usual Yang-Mills theory. In the latter case a generic solution exhibits violent metric oscillations near the singularity. In the Born-Infeld case a generic interior solution is smooth, the metric has the standard Schwarzschild type singularity, and we did not observe internal horizons. Such smoothing of the 'violent' EYM singularity may be interpreted as a result of quantum effects.Comment: Latex, 9 pages, 9 eps figure

Charged Stringy Black Holes With Non-Abelian Hair

Static spherically symmetric asymptotically flat charged black hole solutions are constructed within the magnetic SU(3) sector of the 4-dimensional heterotic string effective action. They possess non-abelian hair in addition to the Coulomb magnetic field and are qualitatively similar to the Einstein-Yang-Mills colored SU(3) black holes except for the extremal case. In the extremality limit the horizon shrinks and the resulting geometry around the origin coincides with that of an extremal abelian dilatonic black hole with magnetic charge. Non-abelian hair exibits then typical sphaleron structure.Comment: 11 pages, LaTex, (7 figures upon request

On a possibility of the blocking of DNA specific recognition sites by hydrogen peroxide molecules during ion beam therapy

Ion beam therapy is one of the most effective methods in treatment of cancer diseases. But up to nowadays, the mechanism of action of heavy ions on cancer cells has not been determined yet. Study of water fragmentation processes during ion beam therapy shows that, among different oxygen species, the significant amount of hydrogen peroxide molecules (H₂O₂) occurs in the сell medium. In the present work, the competitive interaction of H₂O₂ and H₂O molecules with specific DNA recognition sites is studied. Interaction energies of complexes consisting of nucleic bases (adenine, thymine, guanine, and cytosine) together with hydrogen peroxide and water molecules are calculated, using the method of atom-atom potential functions and density functional theory. The atomic groups of nuc leic bases that are more energetically favorable to be bound by hydrogen peroxide rather than by water molecule are found. Formation of such complexes can block the process of DNA replication on different stages and can be one of the mechanisms of ion beam action on cancer cells.Іонна терапія є одним з найефективніших методів лікування ракових захворювань. Але до цього часу механізм дії важких іонів на ракові клітини не визначений. Вивчення процесів фрагментації води під час іонної терапії показує, що серед великої кількості різних фрагментів у середовищі клітини утворюється значна концентрація молекул пероксиду водню (H₂O₂). У роботі наведено результати дослідження конкурентної взаємодії молекул H₂O₂ та H₂O із центрами специфічного розпізнавання ДНК. Енергії взаємодії комплексів, що складаються з нуклеїнових основ (аденін, тимін, гуанін і цитозин) разом з молекулами пероксиду водню і води, обчислені із застосуванням методу атом-атомних потенціальних функцій і теорії функціонала густини. Знайдено атомні групи нуклеїнових основ, які є більш енергетично вигідними для зв’язування з молекулами пероксиду водню, ніж з молекулами води. Утворення таких комплексів може блокувати процес реплікації ДНК на різних етапах і може бути одним з механізмів дії високоенергетичних іонів на ракові клітини.Ионная терапия является одним из наиболее эффективных методов лечения раковых заболеваний. Но до настоящего времени механизм действия тяжелых ионов на раковые клетки не установлен. Изучение процессов фрагментации воды при ионной терапии показывает, что среди большого количества различных фрагментов в клеточной среде образуется значительная концентрация молекул пероксида водорода (H₂O₂). В работе приведены результаты изучения конкурентного взаимодействия молекул H₂O₂ и H₂O с центрами специфического узнавания ДНК. Энергии взаимодействия комплексов, состоящих из нуклеиновых оснований (аденин, тимин, гуанин и цитозин) вместе с молекулами пероксида водорода и воды, рассчитаны с использованием метода атом-атомных потенциальных функций и теории функционала плотности. Найдены атомные группы нуклеиновых оснований, с которыми молекула пероксида водорода связывается значительно энергетически выгоднее, чем молекула воды. Образование таких комплексов может блокировать процесс репликации ДНК на разных стадиях и может быть одним из механизмов воздействия высокоэнергетических ионов на раковые клетки

On superembedding approach to type IIB 7-branes

In search for a dynamical description of Q7-branes, which were known as solutions of supergravity equations and then conjectured to be dynamical objects of type IIB string theory, we study the superembedding description of 7-branes in curved type IIB supergravity superspace. With quite minimal and natural assumptions we have found that there is no place for Q7-branes as dynamical branes in superembedding approach. Our study might give implications for the old-standing problem of the covariant and supersymmetric description of multiple Dp-brane systems.Comment: LaTeX, 40 pages, no figures. V2: 44 pages, misprints corrected, minor cosmetic changes, improvements and extensions of discussion, in particular in the parts devoted to derivation of D7-brane equations of motion (Sec. 3) and in Secs. 4.2; appendices E,F added, footnote on page 30 extended, conclusions remain the same. V3. More misprints correcte

N=2 Super-Born-Infeld from Partially Broken N=3 Supersymmetry in d=4

We employ the non-linear realization techniques to relate the N=1 chiral, and the N=2 vector multiplets to the Goldstone spin 1/2 superfield arising from partial supersymmetry breaking of N=2 and N=3 respectively. In both cases, we obtain a family of non-linear transformation laws realizing an extra supersymmetry. In the N=2 case, we find an invariant action which is the low energy limit of the supersymmetric Born-Infeld theory expected to describe a D3-brane in six dimensions.Comment: 15 pages, no figures, RevTeX4, new comments and references added, some equations corrected, discussion at end of sec. 3 change