Das, Saurya

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https://opus.uleth.ca/handle/10133/3587

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Browsing Das, Saurya by Author "Dey, Anindya"

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    Randall-Sundrum with Kalb-Ramond field: return of the hierarchy problem?
    (2016-01-27) Das, Saurya; Dey, Anindya; SenGupta, Soumitra
    We show that when the antisymmetric Kalb-Ramond field is included in the Randall-Sundrum scenario, although the hierarchy problem can be solved, it requires an extreme fine tuning of the Kalb-Ramond field (about 1 part in 1062). We interpret this as the return of the problem in disguise. Further, we show that the Kalb-Ramond field induces a small negative cosmological constant on the visible brane.
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    Readdressing the hierarchy problem in a Randall-Sundrum scenario with bulk Kalb-Ramond background
    (2015-12-16) Das, Saurya; Dey, Anindya; SenGupta, Soumitra
    We re-examine the fine tuning problem of the Higgs mass, when an antisymmetric two form Kalb-Ramond (KR) field is present in the bulk of a Randall-Sundrum (RS) braneworld. Taking into account the back-reaction of the KR field, we obtain the exact correction to the RS metric. The modified metric also warps the Higgs mass from Planck scale (in higher dimension) to TeV scale (on the visible brane) for a range of values of kr exceeding the original RS value (where k = Planck mass and r = size of extra dimension). However, it requires an extraordinary suppression of the KR field density, indicating the re-appearence of the fine tuning problem in a different guise. The new spacetime also generates a small negative cosmological constant on the visible brane. These results are particularly relevant for certain string based models, where the KR field is unavoidably present in the bulk. We further show that such a bulk antisymmetric KR field fails to stabilize the braneworld.
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    Stability and hierarchy problems in string inspired braneworld scenarios
    (2015-12-15) Das, Saurya; Dey, Anindya; SenGupta, Soumitra
    We generalise the RS braneworld model by taking into account a general stringy bulk containing the scalar dilaton field and the two-form Kalb-Ramond field, apart from gravity. Assuming small fluctuations around a RS background, the back-reacted warp factor is obtained. It is shown that the fine tuning problem in connection with the Higgs mass reappears in a new guise and the effective modular potential fails to stabilise the braneworld.